Disclaimer This presentation has been prepared by Sensei Biotherapeutics, Inc. (the "Company," "we," "us") and is made for informational purposes only. The information set forth herein does not purport to be complete or

Conditionally Active Antibodies for

Immuno-oncology Corporate Deck | June 2024 Exhibit 99.1

Disclaimer This presentation has been

prepared by Sensei Biotherapeutics, Inc. (the "Company," "we," "us") and is made for informational purposes only. The information set forth herein does not purport to be complete or to contain all of the information you may desire.

Statements contained herein are made as of the date of this presentation unless stated otherwise, and the delivery of this presentation at any time shall not under any circumstances create an implication that the information contained herein is

correct as of any time after such date or that information will be updated or revised to reflect information that subsequently becomes available or changes occurring after the date hereof. This presentation contains estimates and other

statistical data made by independent parties and by us relating to market shares and other data about our industry. This presentation also contains "forward-looking" statements as that term is defined in the Private Securities Litigation Reform Act

of 1995 that are based on our management's beliefs and assumptions and on information currently available to management. These forward-looking statements include, without limitation, expectations regarding the development and potential therapeutic

benefits of our product candidates; the expected safety, pharmacokinetic and efficacy profile of our product candidates, including SNS-101; the expected timing of clinical data from our Phase 1/2 clinical trial of SNS-101; the expansion of the Phase

1 clinical trial to include additional patients with specific tumor types; and our belief that our existing cash and cash equivalents will be sufficient to fund our operations at least into the fourth quarter of 2025 and reach midway into Phase 2

clinical studies of SNS-101. When used in this presentation, the words and phrases "designed to," "may," "believes," "intends," "seeks," "anticipates," "plans," "estimates," "expects," "should," "assumes," "continues," "could," "will," "future" and

the negative of these or similar terms and phrases are intended to identify forward-looking statements. Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or

achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Risks and uncertainties that may cause actual results to differ materially include uncertainties

inherent in the development of therapeutic product candidates, such as preclinical discovery and development; conduct of clinical trials and related regulatory requirements, including the risk of delay or cessation of any clinical trials of

Sensei's product candidates; the risk that prior results, such as signals of safety, activity or durability of effect, observed from preclinical trials and early results from the clinical trial of SNS-101, will not be replicated or will not

continue in ongoing or future studies or clinical trials involving Sensei's product candidates, including SNS-101; our reliance on third parties over which we may not always have full control; risks regarding the accuracy of our estimates of

expenses, capital requirements and needs for additional financing; and other risk and uncertainties that are described in our Quarterly Report on Form 10-Q filed with the SEC on May 9, 2024 and our other Periodic Reports filed with the SEC.

Forward-looking statements represent our management's beliefs and assumptions only as of the date of this presentation and include all matters that are not historical facts. Our actual future results may be materially different from what we expect.

Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in the forward-looking statements, even if new information

becomes available in the future. Certain information contained in this presentation relates to, or is based on, studies, publications, surveys and other data obtained from third-party sources and the Company's own internal estimates and

research. While the Company believes these third-party sources to be reliable as of the date of this presentation, it has not independently verified, and makes no representation as to the adequacy, fairness, accuracy or completeness of, any

information obtained from third-party sources. In addition, all of the market data included in this presentation involves a number of assumptions and limitations, and there can be no guarantee as to the accuracy or reliability of such assumptions.

Finally, while we believe our own internal research is reliable, such research has not been verified by any independent source.

Company Highlights Sensei Bio's

proprietary platform is designed to harness conditional activation of antibodies to widen the therapeutic window and enable druggability of promising oncology targets SNS-101, the company's lead asset, is in a Phase 1b study and targets VISTA, a

critical negative regulator of T-cell function and promising immune checkpoint target SNS-101 has demonstrated ability to overcome hurdles associated with drugging VISTA, including: a well-tolerated safety profile, potentially best-in-class PK,

and initial signs of promising clinical activity Three additional early-stage drug candidates Cash runway into the fourth quarter of 2025, which is expected to fund operations midway into Phase 2 studies of SNS-101 Initial Phase 1 expansion data

expected by year-end 2024

Seasoned Leadership Team John Celebi,

MBA President and CEO Edward van der Horst, Ph.D. Chief Scientific Officer Stephanie Krebs, M.S., MBA Chief Business Officer Christopher Gerry, J.D. SVP, General Counsel Ron Weitzman, M.D. Chief Medical Officer (part-time)

Large Commercial Opportunity for

Immuno-Oncology Drugs Market opportunity estimates for PD-1, PDL-1 & anti-CTLA-4 Inhibitors - TD Cowen's Guide to Immuno-oncology GlobalData; Incident cases diagnosed in 8MM 2026 (US, UK, Japan, China, France, Germany, Italy, Spain)

960K Non-Small Cell Lung Cancer (NSCLC) 214K 315K 1.15M Colorectal Cancer (CRC) VISTA's Potential Commercial Impact The checkpoint market is large and growing fast1 Despite the widespread use of checkpoint inhibitors, only 20% of patients

experience an objective response VISTA is implicated in numerous solid tumor types with large patient populations Indications such as CRC see little to no benefit from current treatment options Newly Diagnosed Patients Annually in 20262 ~2.6M new

Industry Problem Sensei's

Solution Conventional antibodies target immune checkpoints that are highly expressed in normal tissues, resulting in: Dose-limiting toxicities due to on-target/off-tumor action Pharmacological sink effect requires higher & more frequent dosing

Suboptimal activity due to poor PK & dose-limiting toxicities Conditionally active antibodies are selectively targeted to the tumor microenvironment, potentially providing: Little or no toxicity due to selective on-target/on-tumor action Lower

& less frequent doses with tumor-specific binding Powerful activity selectively focused on the tumor microenvironment One new IO checkpoint inhibitor approved after the CTLA-4 and PD-1/PD-L1 group 2011 2014 2022 Lack of Tumor Targeting is a

Major Obstacle in IO Innovation Ipilimumab (anti-CTLA-4) Pembrolizumab (anti-PD-1) Relatlimab (anti-LAG-3)

The TMAb Platform: pH-sensitive

Antibodies Selectively Bind to Targets in the Low-pH Tumor Microenvironment Exploits the tumor microenvironment using pH-selective properties Intended to alleviate undesirable PK/PD properties: Dose-limiting toxicities due to

on-target/off-tumor binding Higher and more frequent dosing due to poor pharmacokinetics Bolsters specific activities Unlocks previously undruggable immune targets Sensei's technology identifies pH-sensitive antibodies designed to bind only at

the tumor The tumor microenvironment of pH ~6 is lower than physiological pH of 7.4

Innovative Pipeline of IO Drugs with

Broad Commercial Potential *Sensei has entered into a clinical supply agreement with Regeneron supporting the planned evaluation of SNS-101 in combination with Regeneron's anti-PD-1 therapy Libtayo (cemiplimab) in a Phase 1/2 clinical

trial in solid tumors. *Sensei has entered into a Cooperative Research and Development Agreement (CRADA) with the National Cancer Institute. The goal of this collaborative effort is to further elucidate the role of VISTA in immune checkpoint

resistance and expand the potential of SNS-101 as a combination therapy beyond anti-PD-1.

VISTA is a Potent T cell Checkpoint

Extensively Expressed on Myeloid Cells VISTA is a B7 family member that inhibits T cell activation1 Immunosuppressive function believed to be mediated by PSGL-1 receptor Upregulated on immune suppressive myeloid-derived suppressor cells (MDSCs)

via hypoxia2 Increased expression on tissue infiltrating immune cells upon checkpoint therapy failure3 IS ACTIVATED IN A pH SENSITIVE MANNER T-cell proliferation & activation Extensive VISTA expression on off-tumor myeloid-lineage cells demands

a conditionally active antibody approach VISTA has inherent pH sensitivity: its extracellular domain is uniquely rich in histidines4 Myeloid lineage cell or tumor cell (less common) 1 Wang et al, JEM, 2011 2 Deng et al, Cancer Immunonol Res

2019 3 Gao et al., Nat Med. 2017 4 Johnston et al., Nature 2019

SNS-101 is a pH-sensitive

Antibody Selective for VISTA pH 6.0 pH 7.4 0.218 nM 132 nM (~No binding) Monovalent Affinity (KD) SNS-101 potently inhibits the VISTA:PSGL-1 interaction and all other potential binding partners at pH 6.0 in vitro IC50 = 7nm 2.59

Resolution SNS-101 heavy chain SNS-101 light chain Human VISTA (shown in green and red) Human VISTA epitope for SNS-101 VISTA:SNS-101 co-crystal structure demonstrates SNS-101 encompasses VISTA's PSGL-1 epitope Selectivity for

active VISTApH6 over VISTApH7.4 Blocks the key receptor regulating VISTA's immunosuppressive activity Additional SNS-101 features IgG1 format Active Fc Thisted T. et al. Nature Communications 2024

SNS-101 Designed to Bind VISTA at

the Tumor but Not in the Periphery Pierre Fabre JNJ SNS-101 Control Periphery (Neutral pH) SNS-101 has no detectable binding in peripheral or normal tissues SNS-101 rapidly accumulates in the tumor SNS-101 6h post-dosing Isotype control 6h

post-dosing Blue = tumor Brown = SNS-101 Tumor (Acidic pH)

Competitors Halted Development of

VISTA Antibodies as a Result of Severe Toxicities From Off-Tumor On-Target Activity & Poor PK Dose-limiting toxicity Grade 3 CRS-associated encephalopathy JNJ-61610588 Human Plasma Concentration JNJ-61610588 (CI-8993) was the first anti-VISTA

antibody to be studied in clinical trials in 2016 (NCT02671955) 1 Transient Cytokine Release Syndrome (CRS) observed in several patients at 0.15 mg/kg Transient Grade 3 CRS-associated encephalopathy observed at 0.3 mg/kg, after which Janssen halted

the study Challenging PK profile Non-linear PK, short t1/2 1 Curis, Inc., Corporate Presentation, Feb 2022

SNS-101 is Unique and

Differentiated From Its Peers Johnston et al., Nature 2019; Kineta website; Snyder et al, AACR Annual Meeting 2016; Pierre Fabre website; Hummingbird website; Thakkar et al, J of Immunother Cancer, 2022; PharmAbcine website SNS-101 Sensei Bio

HMBD-002 (Hummingbird) PMC-309 (PharmAbcine) CI-8993; JNJ-61610588 (J&J/Curis) K01401-020; WO180 (Pierre Fabre) KVA12123 (Kineta) VISTA.18 (BMS) Inhibit PSGL-1 Binding pH Sensitive Binding Fc Active Most Advanced Stage (IgG1) (IgG1) (IgG1)

(IgG4) Phase 1 Phase 1 Phase 1 Phase 1 Phase 1 Preclinical Phase 1 (IgG1) (IgG4) (IgG1mut)

Early Development Plan is in

Alignment with Corporate Objectives Corporate Objectives Impact on Study Design PRIMARY Rapidly confirm conditionally active MOA through: Lack of severe CRS Absence of TMDD Reach doses several folds higher than doses where prior

anti-VISTA mAbs experienced DLT Enroll all-comer solid tumor population during dose escalation which included both "hot" and "cold" tumor histologies, allowing for efficient enrollment SECONDARY Explore VISTA's role in both "cold" and "hot"

tumor settings to allow for efficient enrollment and to explore signs of activity in both settings Identify RP2D Enroll selected patient populations to balance cold/hot tumor ratio Explore more discreet range of doses

SNS-101 Phase 1/2 Study *

Libtayo 350 mg Patient enrollment has started for the monotherapy & combination expansion cohorts Cohort A1 0.3 mg/kg N=1 Cohort B1 3.0 mg/kg + Libtayo* N=6 Cohort A2 1.0 mg/kg N=3 Cohort A3 3.0 mg/kg N=3 Cohort A4 10.0 mg/kg N=3 Cohort A5 15.0

mg/kg N=6 Cohort B2 10.0 mg/kg + Libtayo* N=6 Cohort B3 15.0 mg/kg + Libtayo* N=6 CRC Basket (CRC, NSCLC, H&N, Melanoma) Monotherapy Dose Escalation SNS-101 (Q3W) Combination Dose Escalation SNS-101 + Libtayo* (Q3W) Phase 1 Dose Expansion

~ 50 to 70 patients Phase 1 Dose Escalation BOIN design in patients with advanced solid tumors Phase 1 Study Objectives Primary Safety, tolerability, MTD/RP2D Secondary PK, immunogenicity &

anti-tumor activity Phase 2 Single-arm, Simon two-stage minimax design SNS-101 (RP2D) +/- Libtayo (Q3W) Indications TBD Phase 2 Study Objectives Primary Anti-tumor activity Secondary Safety, tolerability, PK & immunogenicity RP2D =

Recommended Phase 2 Dose MTD = Maximum Tolerated Dose CRC = colorectal cancer NSCLC = non small cell lung cancer H&N = head and neck cancer = cleared DLT assessment period Additional tumor types and doses may be considered

for both the monotherapy & combination dose expansion Monotherapy 15 mg/kg Combination 3 mg/kg and 15 mg/kg + Libtayo

Patient Disposition Monotherapy

Combination SNS-101 n=16 (%) SNS-101 + cemi n=18 (%) Enrolled 16 (100.0) 18 (100.0) Treatment Ongoing 2 (13) 2 (11) Discontinued 14 (88) 16 (89) Progressive Disease 13 13 Adverse Event 0 1# Withdrew Consent 0 1 Death Regardless of Causality 1*

0 Death Related to Study Therapy 0 0 Clinical Progression 0 1 * Related to disease progression, not related to SNS-101 (1 mg/kg dose level) # Patient discontinued due to immune mediated AEs of Grade 3 AST and ALT (10 mg/kg + cemi) Data as of

SNS-101 Mono n=16 (%) SNS-101 Combo

n=18 (%) Gender, n (%) Male 12 (75) 11 (61) Female 4 (25) 7 (39) Age, years Median 61.5 62 Min, Max 35, 79 33, 81 Race, n (%) Asian 1 (6) 1 (6) Black or African American 0 2 (11) Not Reported 1 (6) 1 (6) White 14 (88) 14 (77) Ethnicity, n (%) Not

Hispanic or Latino 14 (88) 14 (77) Hispanic or Latino 1 (6) 3 (17) Not reported 1 (6) 1 (6) Baseline ECOG, n (%) 0 6 (37) 4 (22) 1 10 (63) 14 (78) Majority of Patients had Tumor Type Typically Unresponsive to PD-1 Monotherapy Data as of 30April2024

SNS-101 Mono n=16 (%) SNS-101 Combo n=18 (%) Prior lines metastatic therapy Median 2 2.5 Min, Max 0,7 1,7 Prior PD-1/PDL-1 YES% % Yes 8 (50) 4 (22) Cancer Type, n (%) Responsive to PD-1 monotherapy (e.g. "hot" tumors) 3 (19) 2 (11) Head

and Neck 2 0 Kidney 1 2 Typically Unresponsive to PD-1 monotherapy (e.g. "cold" tumors) 13 (81) 16 (89) MSS Colon 4 7 MSS Endometrial 0 1 Esophageal 1 0 Pancreatic 0 3 Sarcoma* 4 2 Other** 4 3 *Sarcoma: Leiomyosarcoma, Ewing

Sarcoma, PEComa, Hemangiopericytoma (mono) and Leiomyosarcoma and Desmoplastic small round cell (combo) **Other Tumor Types: Small cell lung carcinoma, Gallbladder, Adenocystic carcinoma maxillary sinus, and mediastinal carcinoma (mono) and

Ovarian, Duodenal, granulosa cell tumor (germ cell) 85% of enrolled patients had tumors typically unresponsive to PD-1/PD-L1 therapy

SNS-101 Was Well Tolerated as

Monotherapy and in Combination with Cemiplimab *One patient experienced an SAE, Grade 5 bronchial obstruction, that resulted in death; not related to SNS-101, but to disease progression #Two patients experienced Grade 1 CRS ^One patient experienced

Grade 2 rash maculo-papular at 3 mg/kg + cemi ^One patient experienced Grade 3 Diabetic Ketoacidosis at 3 mg/kg + cemi ^Two patients experienced elevated liver enzymes both at 10 mg/kg + cemi (one pt with Grade 3 ALT and Grade 1 AST and

one pt with Grade 3 AST and ALT which resulted in discontinuation from treatment) SNS-101 n=16 (%) SNS-101 + cemi n=18 (%) At least 1 TEAE 13 (81) 14 (78) At least 1 SAE 1 (6) 8 (44) Grade 3 TEAE 2 (13) 8 (44) At least 1 TEAE leading to

discontinuation 1* (6) 1 (5) DLTs 0 0 AESI 1 (6) 5 (28) Immune-mediated^ 0 4 (22) CRS# 1 (6) 1 (6) Preferred Term SNS-101 Mono n=16 SNS-101 Combo n=18 Total n=34 Fatigue 0 5 5 Cough 3 1 4 Pleural effusion 1 2 3 Pyrexia 2 1 3 Rash maculopapular

1 2 3 Alanine aminotransferase increased 0 2 2 Anaemia 0 2 2 Aspartate aminotransferase increased 0 2 2 Blood bilirubin increased 0 2 2 Chills 1 1 2 COVID-19 1 1 2 Cytokine release syndrome 1 1 2 Dermatitis acneiform 2 0 2 Hypokalemia 1 1 2

Hypomagnesemia 1 1 2 Infusion related reaction 0 2 2 Lymphocyte count decreased 0 2 2 Nausea 0 2 2 Pruritis 0 2 2 Most Frequently Occurring AEs ( 2 Overall) Regardless of Causality Summary of Adverse Events Data as of 30April2024 No

dose-limiting toxicities observed Majority of AEs were Grade 1 or 2 Two patients experienced Grade 1 CRS, suggesting that CRS is a class effect of VISTA-targeting antibodies

SNS-101 Has Only Been Associated

with Mild IRR/CRS-like Adverse Events (Unlike First Generation VISTA Antibodies) Subject Number Dose Level Adverse Event Preferred Term (Event description) Severity (Grade) Time of Onset relative to start of Infusion 01-010 SNS-101 15.0 mg/kg

Cytokine Release Syndrome (Chills and fever) Grade 1 C1D1 ~4 hours post SNS-101 Infusion 01-013 SNS-101 15.0 mg/kg + cemi Cytokine Release Syndrome (Chills, no fever) Grade 1 C1D1 ~5 hours post SNS-101 Infusion 01-009 SNS-101 3.0 mg/kg

+ cemi Infusion-related reaction (Chills and flushing) Grade 2 C2D1 At the end of the SNS-101 Infusion 04-015 SNS-101 15.0 mg/kg + cemi Infusion-related reaction (chest tightness, muscle aches, hypotension) Patient also reported grade 1