CERTAIN INFORMATION HAS BEEN OMITTED BECAUSE IT IS BOTH NOT MATERIAL AND WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED ARCUS BIOSCIENCES, INC. COMMON STOCK PURCHASE AGREEMENT This Common Stock Purchase Agreement (

[***] = CERTAIN INFORMATION HAS BEEN OMITTED BECAUSE IT IS BOTH NOT MATERIAL AND WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED

ARCUS BIOSCIENCES, INC.

COMMON STOCK PURCHASE AGREEMENT

This Common Stock Purchase Agreement (this "Agreement") is dated as of May 27, 2020, by and between Arcus Biosciences, Inc., a Delaware corporation (the "Company"), and Gilead Sciences, Inc., a Delaware corporation ("Gilead").

WHEREAS, subject to the terms and conditions set forth in this Agreement, the Company desires to issue and sell to Gilead, and Gilead desires to purchase from the Company, shares of common stock of the Company as more fully described in this Agreement; and

WHEREAS, concurrently herewith, the Company and Gilead have entered into an Option, License and Collaboration Agreement (the "Collaboration Agreement") and an Investor Rights Agreement (the "Investor Rights Agreement").

NOW, THEREFORE, in consideration of the mutual covenants contained in this Agreement, and for other good and valuable consideration the receipt and adequacy of which are hereby acknowledged, the Company and Gilead agree as follows:

1.1.Definitions. In addition to the terms defined elsewhere in this Agreement, for all purposes of this Agreement, the following terms have the meanings set forth in this Section 1.1:

1.1.1"5-Day Closing Price" means, for any date, (a) the sum of the "official closing price" (as defined by NYSE) of the Common Stock for the period of five (5) consecutive Trading Days through and including such date, (b) divided by five (5), and (c) rounded to two decimal places.

1.1.2"Additional Closing" has the meaning set forth in Section 2.3.2 hereof.

1.1.3"Additional Closing Date" has the meaning set forth in Section 2.3.2 hereof.

1.1.4"Additional Shares" means the shares of Common Stock subject to an Additional Shares Purchase Notice.

1.1.5"Additional Shares Purchase Notice" has the meaning set forth in Section 2.3.2 hereof.

1.1.6"Additional Shares Purchase Notice Date" means the date on which Gilead delivers an Additional Shares Purchase Notice to the Company.

1.1.7"Additional Shares Purchase Price" means, with respect to an Additional Closing, a price per share equal to the greater of (a) 120% of the 5-Day Closing Price calculated on the Additional Shares Purchase Notice Date with respect to such Additional Closing and (b) the Initial Shares Purchase Price.

1.1.8"Affiliate" means any Person that, directly or indirectly through one or more intermediaries, Controls or is Controlled by or is under common Control with a Person.

1.1.9"Aggregate Additional Purchase Price" means, with respect to an Additional Closing, the dollar amount obtained by multiplying the number of Additional Shares to be purchased at such Additional Closing by the applicable Additional Shares Purchase Price.

1.1.10"Aggregate Initial Purchase Price" means the dollar amount obtained by multiplying the number of shares of Common Stock constituting the Initial Shares by the Initial Shares Purchase Price.

1.1.11"Anti-Corruption Laws" has the meaning set forth in Section 3.1.17 hereof.

1.1.12"Antitrust Approval" means, as the context requires, any consent, approval, expiration or termination of any waiting period, or any other authorization required under the applicable Antitrust Laws from any applicable Antitrust Authority to effect any of (a) Gilead's purchase of the Initial Shares, (b) Gilead's purchase of Additional Shares or (c) the transactions contemplated by the Collaboration Agreement or the Investor Rights Agreement.

1.1.13 "Antitrust Authority" means any applicable Governmental Authority exercising authority with respect to any Antitrust Laws.

1.1.14"Antitrust Laws" means any applicable laws, rules and regulations, including any rules, regulations, guidelines or other requirements of Governmental Authorities, governing merger control, competition, monopolies or restrictive trade practices, including the HSR Act and the rules and regulations promulgated thereunder.

1.1.15"Beneficial Ownership" or "Beneficially Owns" shall have the meaning set forth in Rule 13d-3 under the Securities Exchange Act.

1.1.16"Business Day" means a day other than (a) a Saturday or a Sunday, (b) a bank or other public holiday in California, United States, (c) the Sunday through Saturday containing July 4th or (d) the period commencing on December 25th and ending on January 1st (inclusive).

1.1.17"Closing" means, as applicable, the Initial Closing or an Additional Closing.

1.1.18"Closing Date" means, as applicable, the Initial Closing Date or an applicable Additional Closing Date.

1.1.19"Collaboration Agreement" has the meaning set forth in the recitals.

1.1.20"Commission" means the United States Securities and Exchange Commission.

1.1.21"Commission Rule 144" means Rule 144 promulgated by the Commission under the Securities Act.

1.1.22"Common Stock" means the Company's common stock, par value $0.0001 per share.

1.1.23"Company Capitalization" means, as of any date of measurement, the total number of outstanding shares of voting capital stock of the Company.

1.1.24"Control," including the terms "Controlling," "Controlled by" and "under common Control with," means the possession, directly or indirectly, of the power to direct or cause the direction of the management and policies of a person, whether through the ownership of voting shares, by contract or otherwise.

1.1.25"Cross-Receipt" means a cross-receipt substantially in the form of Exhibit A hereto.

1.1.26"Designated Event" has the meaning set forth in Section 4.7.

1.1.27"Designated Event Notice" has the meaning set forth in Section 4.7.

1.1.28"Disqualification Event" has the meaning set forth in Section 3.1.20 hereof.

1.1.29"DOJ" has the meaning set forth in Section 2.4 hereof.

1.1.30"Entity" has the meaning set forth in Section 3.1.18(a) hereof.

1.1.31"Evaluation Date" has the meaning set forth in Section 3.1.9 hereof.

1.1.32"Exchange Act" means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

1.1.33"Exercise Period" shall mean the period beginning on the Initial Closing Date and continuing until the fifth anniversary thereof.

1.1.34"FDA" has the meaning set forth in Section 3.1.12 hereof.

1.1.35"FTC" has the meaning set forth in Section 2.4 hereof.

1.1.36"GAAP" has the meaning set forth in Section 3.1.8(b) hereof.

1.1.37"Governmental Authority" means any multi-national, federal, state, local, municipal or other government authority of any nature (including any governmental division, subdivision, department, agency, bureau, branch, office, commission, council, court or other tribunal, as well as any securities exchange or securities exchange authority, including NYSE).

1.1.38"HSR Act" means the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended.

1.1.39"Individual" has the meaning set forth in Section 3.1.18(a) hereof.

1.1.40"Initial Closing" means the closing of the sale of the Initial Shares pursuant to Section 2.3.1 hereof.

1.1.41"Initial Closing Date" has the meaning set forth in Section 2.3.1 hereof.

1.1.42"Initial Shares" means 5,963,029 shares of Common Stock, subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization with respect to the Common Stock prior to the Initial Closing.

1.1.43"Initial Shares Purchase Price" means $33.54 per share, subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization with respect to the Common Stock.

1.1.44"Intellectual Property" has the meaning set forth in Section 3.1.14 hereof.

1.1.45"Issuer Covered Person" has the meaning set forth in Section 3.1.20 hereof.

1.1.46"Investor Rights Agreement" has the meaning set forth in the recitals.

1.1.47"Law" or "law" means any supranational, national, federal, state, regional, provincial, local or municipal constitution, treaty, law, statute, ordinance, code, determination, principle of common law or any other requirement having the effect of law of any Governmental Authority (including any rule, regulation, plan, injunction, judgment, order, award, decree, ruling, requirement, guidance, policy or charge thereunder or related thereto), in each case as amended as of the date hereof, whether in the United States or a foreign jurisdiction.

1.1.48"Liens" means a lien, charge, pledge, security interest, encumbrance, right of first refusal, mortgage, claim, easement, right-of-way, option, title retention agreement, preemptive right or other restriction.

1.1.49"NYSE" means the New York Stock Exchange.

1.1.50"OFAC" has the meaning set forth in Section 3.1.18(a) hereof.

1.1.51"Permits" has the meaning set forth in Section 3.1.12 hereof.

1.1.52"Person" means an individual, sole proprietorship, partnership, limited partnership, limited liability partnership, corporation, limited liability company, business trust, joint stock company, trust, unincorporated association, joint venture or other similar entity or organization, including a government or political subdivision, department or agency of a government.

1.1.53"Required Approvals" has the meaning set forth in Section 3.1.3 hereof.

1.1.54"Sanctioned Countries" has the meaning set forth in Section 3.1.18(a) hereof.

1.1.55"Sanctions" has the meaning set forth in Section 3.1.18(a) hereof.

1.1.56"SEC Report" means any report filed by the Company with the Commission under the Exchange Act.

1.1.57"Securities Act" means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

1.1.58"Shares" means the Initial Shares and all Additional Shares.

1.1.59"Trading Day" means a day on which NYSE is open for trading.

1.1.60"Trading Market" means any of the following markets or exchanges on which the Common Stock is listed or quoted for trading on the date in question: the NYSE, the NYSE American, the Nasdaq Capital Market, the Nasdaq Global Market or the Nasdaq Global Select Market (or any successors to any of the foregoing).

1.1.61"Transfer Agent" means Computershare Trust Company, N.A., with a mailing address of 150 Royall Street, Canton, Massachusetts 02021, or any successor transfer agent of the Common Stock.

1.1.62"Valid Account Details" means, with respect to any bank account, the valid (a) name of bank, (b) bank address, (c) account number and (d) ABA routing number.

PURCHASE AND SALE OF SHARES

2.1.Purchase of Shares. Subject to the terms and conditions of this Agreement, at the Initial Closing, the Company will issue and sell to Gilead, and Gilead will purchase from the Company, the Initial Shares, at a price per share equal to the Initial Shares Purchase Price, for an aggregate purchase price equal to the Aggregate Initial Purchase Price. Subject to the terms and conditions of this Agreement, at each Additional Closing, the Company will issue and sell to Gilead, and Gilead will purchase from the Company, the applicable Additional Shares, at a price

per share equal to the Additional Shares Purchase Price, for an aggregate purchase price equal to the Aggregate Additional Purchase Price for such Additional Closing.

2.2.Payment. At (a) the Initial Closing, Gilead will pay the Aggregate Initial Purchase Price and (b) each Additional Closing, Gilead will pay the applicable Aggregate Additional Purchase Price, in each case by wire transfer of immediately available funds in accordance with the Valid Account Details, which Valid Account Details together with a Form W-9 will have been provided by the Company to Gilead at least five (5) Business Days prior to the applicable Closing Date. The Company shall cause delivery of the applicable Shares at each Closing to be made in book-entry form to an account of Gilead specified in writing by Gilead at the Transfer Agent.

2.3.1The Initial Closing shall occur at 10:00 am (New York City time) on such date as the parties may select, not later than the third Business Day after satisfaction or (to the extent permitted by law) waiver of the conditions set forth in Section 2.7 (Conditions to the Initial Closing) (other than those conditions that by their terms are to be satisfied at the Initial Closing, but subject to the satisfaction or (to the extent permitted by law) waiver of those conditions), unless such other place, time and date shall be agreed in writing between the Company and Gilead (such date, the "Initial Closing Date").

2.3.2At any time and from time to time during the Exercise Period, Gilead shall have a right (but not the obligation) to purchase from the Company, and the Company shall issue and sell to Gilead, Additional Shares, at the applicable Additional Shares Purchase Price. Gilead may exercise this right (but not more than once in any period of 90 days; provided that, following the delivery of a Designated Event Notice, Gilead may exercise this right at any time, without regard to such 90 day limitation) by giving written notice to the Company (each, an "Additional Shares Purchase Notice"). Each Additional Shares Purchase Notice shall (a) set forth the applicable Additional Closing Date and (b) specify the number of Additional Shares to be purchased on such Additional Closing Date; provided that such number of Additional Shares, if purchased, would not cause, collectively, Gilead and its Controlled Affiliates to Beneficially Own a number of shares of Common Stock greater than 35% of the Company Capitalization as of the applicable Additional Closing Date. The Closing of each such sale of Additional Shares shall occur at 10:00 am (New York City time) as promptly as practicable following the date of the Additional Shares Purchase Notice and not later than the third Business Day after satisfaction or (to the extent permitted by law) waiver of the conditions set forth in Section 2.8 (Conditions to each Additional Closing) (other than those conditions that by their terms are to be satisfied at the Additional Closing, but subject to the satisfaction or (to the extent permitted by law) waiver of those conditions), unless such other place, time and date shall be agreed in writing between the Company and Gilead (each such date, an "Additional Closing Date," and each such closing, an "Additional Closing"). For clarity, Gilead may rescind or revoke an Additional Shares Purchase Notice at any time in its sole discretion prior to the applicable Additional Closing Date.

2.4.Antitrust Approvals. With respect to each proposed purchase of Additional Shares, Gilead shall determine, in its sole discretion, whether any Antitrust Approvals will or may be required in connection with the proposed purchase of Additional Shares, and shall hold the

Company harmless from any claim that any purchase was made without a required Antitrust Approval. Upon Gilead's request, including any such request made prior to delivery of an Additional Shares Purchase Notice, the Company shall promptly provide Gilead with information and assistance as may be reasonably necessary for Gilead to make such determination. If Gilead determines that Antitrust Approvals are or may be required (or if additional information is necessary for Gilead to make such a determination), Gilead shall so notify the Company in writing together with the delivery of an Additional Shares Purchase Notice, and the parties shall provide each other promptly with information and assistance as may be reasonably necessary and use reasonable efforts, in each case, promptly to obtain all required Antitrust Approvals for the consummation of the applicable Additional Closing and the transactions contemplated thereby and shall keep each other apprised of the status of any communications with, and any inquiries or requests for information from, the Federal Trade Commission ("FTC"), Department of Justice ("DOJ") and any other applicable Antitrust Authority and shall respond promptly to any such inquiry or request; provided that neither party shall be required to consent to the divestiture or other disposition of any of its or its Affiliates' assets, consent to any other structural or conduct remedy or otherwise restrict or limit its or its Affiliates' freedom of action. Each party shall cooperate with the other and use reasonable efforts to facilitate and expedite the identification and resolution of any such issues and, consequently, the expiration of any applicable waiting period under Antitrust Laws. Such reasonable efforts and cooperation shall include: (a) keeping each other promptly informed of all communications with and providing copies of all written communications, from and to any Antitrust Authority, and sharing drafts of written submissions to any Antitrust Authority in advance of submission and taking comments of the other into account in good faith; however, the parties may redact submissions for privilege and the parties also may request that distribution of submissions be limited to outside counsel only and (b) conferring with each other regarding contacts with and responses to, and permitting the other to participate in all meetings and video conferences or substantive telephone conversations with, to the extent not prohibited by, the FTC, DOJ or other any other Antitrust Authority; provided that subject to its undertakings and obligations under this Section 2.4 to take into consideration in good faith the Company's views, suggestions and comments regarding the strategy to be pursued for obtaining all required Antitrust Approvals, Gilead shall lead the strategy to obtain all such approvals, and if there is a dispute between Gilead and the Company, the final determination as to the appropriate course of action shall be made by Gilead. Each Party shall be responsible for its own costs and expenses associated with obtaining any required Antitrust Approvals, but (i) Gilead shall be responsible for payment of all fees to any Antitrust Authority with respect to antitrust filings made pursuant to the HSR Act or foreign antitrust law, and (ii) [***].

2.5.Initial Closing Deliverables.

2.5.1At the Initial Closing, the Company will deliver to Gilead:

2.5.2At the Initial Closing, Gilead will deliver to the Company:

2.6.Additional Closing Deliverables.

2.6.1At each Additional Closing, the Company will deliver to Gilead:

2.6.2At each Additional Closing, Gilead will deliver to the Company:

2.7.Conditions to the Initial Closing.

2.7.1The obligations of Gilead hereunder in connection with the Initial Closing are subject to the following conditions being satisfied or waived:

2.7.2The obligations of the Company hereunder in connection with the Initial Closing are subject to the following conditions being satisfied or waived:

2.8.Conditions to each Additional Closing.

2.8.1The obligations of Gilead hereunder in connection with each Additional Closing are subject to the following conditions being satisfied or waived:

2.8.2The obligations of the Company hereunder in connection with each Additional Closing are subject to the following conditions being satisfied or waived:

REPRESENTATIONS AND WARRANTIES

3.1.Representations and Warranties of the Company. The Company hereby makes the following representations and warranties to Gilead as of the date hereof, as of the Initial Closing Date and, with respect to the representations and warranties set forth in Sections 3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.1.5, 3.1.6, 3.1.7 and 3.1.21 also as of any Additional Closing Date (except, in each case, for the representations and warranties that speak as of a specific date, which shall be made as of such date).

3.1.1Organization and Qualification. The Company and each of its subsidiaries are duly organized, validly existing as a corporation and in good standing under the laws of their respective jurisdictions of organization. The Company and each of its subsidiaries are duly licensed or qualified as a foreign corporation for transaction of business and in good standing under the laws of each other jurisdiction in which their respective ownership or lease of property or the conduct of their respective businesses requires such license or qualification, and have all corporate power and authority necessary to own or hold their respective properties and to conduct their respective businesses as described in the SEC Reports (defined below), except where the failure to be so qualified or in good standing or have such power or authority would not, individually or in the aggregate, reasonably be expected to have a material adverse effect.

3.1.2Authorization; Enforcement. The Company has the requisite corporate power and authority to enter into and to consummate the transactions contemplated by this Agreement and otherwise to carry out its obligations hereunder. The execution and delivery of this Agreement by the Company and the consummation by it of the transactions contemplated hereby (including the issuance and sale of the Shares by the Company) have been duly authorized by all necessary action on the part of the Company and no further action is required by the Company, the Company's Board of Directors or the Company's stockholders in connection herewith other than the Required Approvals (as defined below). This Agreement has been duly executed by the Company and, when delivered in accordance with the terms hereof, will constitute the valid and binding obligation of the Company enforceable against the Company in accordance with its terms, except (a) as limited by general equitable principles and applicable bankruptcy, insolvency, reorganization, moratorium and other laws of general application affecting enforcement of creditors' rights generally and (b) insofar as indemnification and contribution provisions may be limited by applicable law.

3.1.3No Conflicts; Filings, Consents and Approvals. The execution, delivery and performance of this Agreement by the Company and the consummation by the Company of the transactions contemplated hereby (including the issuance of the Shares) will not (i) conflict with or result in a violation of any provision of the Company's Amended and Restated Certificate of Incorporation or Amended and Restated Bylaws, each as in effect on the date hereof, (ii) violate

or conflict with, or result in a breach of any provision of, or constitute a default under, any agreement, indenture, or instrument to which the Company is a party, or (iii) result in a violation of any Law applicable to the Company, except in the case of clauses (ii) and (iii) only, for such conflicts, breaches, defaults, and violations as would not reasonably be expected to have, a material adverse effect on the Company or result in a liability for Gilead. The Company is not required to obtain any consent, waiver, approval, authorization or order of, give any notice to, or make any filing or registration with, any court or other federal, state, local or other Governmental Authority or other Person in the United States in connection with the execution, delivery and performance by the Company of this Agreement (including the offer, sale or issuance of the Shares by the Company), other than the obtaining of the Antitrust Approvals and the listing of the Shares on the NYSE, or as may be required under applicable state securities laws or the by-laws and rules of the Financial Industry Regulatory Authority (collectively, the "Required Approvals").

3.1.4Issuance of Shares. The Shares are duly authorized and, when issued and paid for in accordance with this Agreement, will be validly issued, fully paid and nonassessable, free and clear of all Liens, other than restrictions on transferability under the Investor Rights Agreement and applicable federal securities laws. The Shares are not and will not be subject to any preemptive rights held by any holders of any security of the Company or any similar contractual rights granted by the Company to any Person.

3.1.5Material Changes; Undisclosed Events, Liabilities or Developments. Since the date of the audited financial statements included within the Company's Annual Report on Form 10-K, filed with the Commission on March 5, 2020, except as specifically disclosed in a subsequent SEC Report, there has been no event, occurrence or development that has had or that could reasonably be expected to, either individually or in the aggregate, have a material adverse effect on the business, condition (financial or other), assets, liabilities or results of operations of the Company, taken as a whole.

3.1.6No General Solicitation. Neither the Company, nor any of its Affiliates, nor any Person acting on its or their behalf, has engaged in any form of general solicitation or general advertising (within the meaning of Regulation D under the Securities Act) in connection with the offer or sale of the Shares.

3.1.7Private Placement. Neither the Company nor any Person acting on its behalf, has, directly or indirectly, made any offers or sales of any security or solicited any offers to buy any security, under any circumstances that would require registration of the Shares under the Securities Act. Subject to the accuracy of the representations made by Gilead in Section 3.2, the Shares will be issued and sold to Gilead in compliance with applicable exemptions from the registration and prospectus delivery requirements of the Securities Act and the registration and qualification requirements of all applicable securities Laws of the states of the United States. The Company has not engaged any brokers, finders or agents, or incurred, or will incur, directly or indirectly, any liability for brokerage or finder's fees or agents' commissions or any similar charges in connection with this Agreement and the transactions contemplated hereby, other than brokerage or finder's fees or agent's commissions or similar charges for which the Company is wholly responsible.