DISCLAIMER | Forward Looking Statements Certain information contained in this presentation includes "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21

Breaking Boundaries. Igniting Change.

Nasdaq: IOBT Jefferies Healthcare Conference November 2025 Exhibit 99.1

DISCLAIMER | Forward Looking

Statements Certain information contained in this presentation includes "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as

amended, related to our business plan, clinical trials and regulatory submissions. We may, in some cases, use terms such as "may," "should," "would," "expects," "plans,"

"anticipates," "could," "intends," "target," "projects," "contemplates," "believes," "estimates," "predicts," "potential" or

"continue" or other words that convey uncertainty of the future events or outcomes to identify these forward-looking statements. Our forward-looking statements are based on current beliefs and expectations of our management team that

involve risks, potential changes in circumstances, assumptions, and uncertainties. Any or all of the forward-looking statements may turn out to be wrong or be affected by inaccurate assumptions we might make or by known or unknown risks and

uncertainties. These forward-looking statements are subject to risks and uncertainties including risks related to the execution of our business plan, success and timing of our clinical trials or other studies and the other risks set forth in our

filings with the U.S. Securities and Exchange Commission. For all these reasons, actual results and developments could be materially different from those expressed in or implied by our forward-looking statements. You are cautioned not to place

undue reliance on these forward-looking statements, which are made only as of the date of this presentation. We undertake no obligation to publicly update such forward-looking statements to reflect subsequent events or circumstances, except as

Cylembio is an investigational drug

candidate that has not been approved for marketing by the US FDA or other regulatory authorities.

IO Biotech | Breaking boundaries.

Igniting change PHASE 3 RESULTS *Statistical significance threshold for this study was p 0.045. 1. https://gco.iarc.fr/today/en/; 2. https://seer.cancer.gov/statfacts/html/melan.html; 3. Melanoma Research Alliance; 4. Larkin et al. N Engl J

Med 2019;381:1535-1546; 5. Robert et al. Lancet Oncol 2019;20:1239-1251; 6. Tawbi et al. N Engl J Med 2022;386:24-34; 7. Weber et al. Oncologist. 2016;21(10):1230-1240; 8. Evaluate Pharma 2025 Cylembio is an ideal combination partner

potential for clinical improvement across a number of combination agents without additional systemic toxicity PLATFORM POTENTIAL OPPORTUNITY Improved clinical effect observed without significant added systemic toxicity vs. pembro alone 19.4

vs. 11.0 Months mPFS HR=0.77 (CI 0.58-1.00) (p=0.056)* PFS improvement observed across virtually all subgroups & stratification factors Demonstrated clinical improvement; Narrow miss on statistical significance Potential broad application

with data across 3 indications (Melanoma, SCCHN, NSCLC), and pipeline potentially addressing other difficult-to-treat cancers of patients progress within one year of treatment: novel combinations are needed to improve patient outcomes 50%

15,000 US patients with advanced melanoma $5.6 billion US market opportunity growing at 9% Plan to align on new phase 3 design with FDA & discuss submission of MAAs based on IOB-013 data with EMA 2025

1. Melanoma of the Skin - Cancer

Stat Facts; 2. https://seer.cancer.gov/statfacts/html/melan.html; Bajaj. J Natl Cancer Inst. 2020; Leeneman. EJC. 2021; Zhang. Adv Ther. 2023; Eggermont. J of Clin Onc. 2019; Eggermont. NEJM. 2022; Wolchok. J Clin Oncol. 2022; Miller,

CA Cancer J Clin, 2019; National Comprehensive Cancer Network (NCCN): Clinical Practice Guidelines in Oncology (NCCN Guidelines ); Melanoma Version 2.2025 THE MELANOMA PATIENT JOURNEY 1 Disease Presentation Primary Care Physician or

Dermatologist 2 Diagnosis & Referral Newly Diagnosed Melanoma in ~100,0001 patients annually in the U.S. 3 Resectable Melanoma ~92,000 patients2 Surgical candidate? Residual Disease Post-Surgery? Neo/adjuvant treatment and Surgical Resection 4

Unresectable or Metastatic Melanoma ~15,000 patients2: High unmet medical need still exists due to lack of efficacy and toxicity issues from available SOC 1L Treatment Selection, Insurance and Access (anti-PD1 monotherapy; anti PD1 combination with

either anti-CTLA4 or anti LAG3 agents) Patient Checks in at the Infusion Center Product Preparation & Delivery to Infusion Center Product Administration Yes No Yes Cylembio has potential to address a high unmet medical need by

improving clinical effect without adding systemic toxicity

Cylembio in First-Line Advanced

Primary endpoint PFS by central review

Secondary/exploratory endpoints ORR, DRR, CRR, OS, DoR, TTR, DCR Incidence of AEs and SAEs Quality of life Biomarkers in blood and tumor tissue will also be assessed Stratification Endpoints Randomization 407 enrolled across >100 sites in Europe,

Australia, South Africa, Israel and the US Advanced melanoma Unresectable stage III Metastatic stage IV > 6 months after neoadjuvant/ adjuvant anti-PD-1 Measurable disease (RECIST 1.1) ECOG performance status 0-1 Stable CNS disease is allowed

Eligibility criteria 1L, first-line; AE, adverse event; BLA, Biologics License Application; CNS, central nervous system; CRR, complete response rate; DCR, disease control rate; DoR, duration of response; DRR, durable response rate; ECOG, Eastern

Cooperative Oncology Group; IA, interim analysis; IDMC, independent data monitoring committee; mut, mutation; ORR, objective response rate; OS, overall survival; PD-1, programmed cell death protein 1; PFS, progression-free survival; ph, phase; q3w,

once every 3 weeks; RECIST, Response Evaluation Criteria in Solid Tumors; SAE, serious adverse event; TTR, time to response; WT, wild-type. ClinicalTrials.gov: NCT05155254. Disease Stage (Low vs high risk)* BRAF (mut vs WT) *Stage III and

IV M1a-b vs. stage IV M1c-d IO102-IO103 and Pembrolizumab 200mg q3w N= 203 Pembrolizumab 200mg q3w N=204 1:1 Clinical trial design Patients in both arms can be treated for up to 2 years IOB-013 CLINICAL TRIAL DESIGN | Phase 3 Advanced Melanoma

Clinical Trial Design

PHASE 3 TRIAL | Cylembio demonstrated

PFS improvement across virtually all pre-specified subgroups and stratification factors Topline results released August 2025 *Statistical significance threshold for this study was p 0.045. **Post-hoc analysis. Source: Data on file. Overall

Survival trend favoring Cylembio combination arm, OS not yet mature HR = 0.79 (CI 0.57, 1.10); Well-tolerated with no significant added systemic toxicity compared to pembrolizumab alone Median progression free survival, ITT analysis: Cylembio plus

pembrolizumab 19.4 months vs. 11.0 months for patients treated with pembrolizumab alone, HR=0.77 (CI 0.58-1.00) (p=0.056)* In PD-L1 negative group, mPFS was 16.6 months in patients treated with Cylembio plus pembrolizumab compared to 3.0 months in

patients treated with pembro alone, HR: 0.54 (CI 0.35-0.85) (nominal p=0.006) Excluding patients with prior anti-PD1 exposure** (n=36): mPFS was 24.8 months vs. 11.0 months HR: 0.74 (CI 0.56-0.98) (nominal p=0.037) (n=371)

PHASE 3 TRIAL | Early Separation of

PFS Curves at 3 Months - Widening Over Time Source: Company data on file. Kaplan-Meier estimate of PFS in ITT determined by BICR per RECISTv1.1 and stratified by PD-L1 status and disease stage

PHASE 3 TRIAL | Trend in Overall

Survival Benefiting Cylembio (not yet mature) separating early and widening HR, 0.79; 95% CI, 0.57 to 1.10 OS not mature HR 0.79 is in line with 12 month OS data reported from other IO combinations Source: Company data on file. Kaplan-Meier

estimate of OS in ITT and stratified by PD-L1 status and disease stage Key takeaways

SAFETY DATA | Treatment with

Cylembio did not add significant systemic toxicity compared to patients treated with pembrolizumab monotherapy Source: Company data on file. Acronyms: AE, adverse event; CTCAE, common terminology criteria for adverse events; MedDRA, medical

dictionary for medical regulatory activities; N, number. IO102-IO103 plus pembrolizumab, N=200 Pembrolizumab, N=198 Any grade, n (%) Grade 3-4, n (%) Any grade, n (%) Grade 3-4, n (%) Any AEs* 194 (97.0) 75 (37.5) 187 (94.4) 69 (34.8) AE

leading to discontinuation of study treatment 31 (15.5) 15 (7.5) 31 (15.7) 13 (6.6) Serious AEs 64 (32.0) 44 (22.0) 64 (32.3) 39 (19.7) Treatment-related AEs 171 (85.5) 29 (14.5) 161 (81.3) 31 (15.6) Treatment-related serious AE 19 (9.5) 13 (6.5) 25

(12.6) 15 (7.6) Immune-mediated AEs 68 (34.0) 17 (8.5) 76 (38.4) 18 (9.1) Investigator assessed immune-related AE not included in the immune-mediated AE definition 102 (51.0) 13 (6.5) 99 (50.0) 15 (7.6) Injection-site reaction (grouped

term) 112 (56.0) 1 (0.5) - - *The AEs leading to death among patients who received IO102-IO103 plus pembrolizumab (n=4) or pembrolizumab (n=5) were considered not related to the study treatment by the investigators Safety

analyses conducted on all randomized patients who received 1 dose of assigned trial medication; AEs classified by the MedDRA version 28.0 and graded by CTCAE version 5.0 Treatment-related AE: events possibly or probably

related to either IO102-IO103 or Pembrolizumab Immune-mediated AE defined by KEYTRUDA adverse events of special interest list version 28.0 Immune-related events based on the investigator assessment

MARKET OPPORTUNITY IN ADVANCED

MELANOMA | Cylembio profile has potential to fulfill significant unmet needs and drive market leadership 1. https://gco.iarc.fr/today/en/; 2. https://seer.cancer.gov/statfacts/html/melan.html; 3. Melanoma Research Alliance; 4. Larkin et al. N

Engl J Med 2019;381:1535-1546; 5. Robert et al. Lancet Oncol 2019;20:1239-1251; 6. Tawbi et al. N Engl J Med 2022;386:24-34; 7. Weber et al. Oncologist. 2016;21(10):1230-1240; 8. Evaluate Pharma 2025 Melanoma incidence is increasing1-3 ~331,000

patients newly diagnosed annually (global) ~58,000 patient deaths annually (global) 30% 5-year survival rate for patients in stage IV Cylembio profile has potential to drive market leadership8 2030 2024 14 12 10 8 6 4 2 +9% 13.2 9.4 Forecast

global Melanoma Drug Sales in USD billions US CAGR Patients and physicians seek more effective treatment options4-7 ~50% of patients progress within one year of treatment; novel combinations are needed to improve patient outcomes

Cylembio is an ideal combination

partner candidate that we believe could deliver clinical activity without tolerability issues: IO102-IO103 has demonstrated improvement in PFS, trend towards long and durable response including in hard-to-treat subgroups, with favorable safety

across a number of combination agents in clinical studies IO102-IO103 + nivolumab Clinically meaningful data in all patients, even those with poor prognostic factors Biomarkers linked to responding patients IO102-IO103 + pembrolizumab Clinically

meaningful improvement in PFS across subgroups; narrow miss on statistical significance* Early separation of PFS curves and durability Induction of T-cells; Dual seems to follow clinical response IO102-IO103 + nivolumab + relatlimab Three sites,

enrollment completed Preliminary data as of Sept. 2025 shows early PFS trend suggestive of improved clinical activity vs. historic data with a-PD-1/ a-Lag-3 combination; PFS data (n=32) is not yet mature No new safety signal, safety profile

consistent with a-PD-1/a-Lag-3 data IO102-IO103 + anti PD-1 + Lag-3 inhibitor Adaptive Ph3 study designed to be relevant for evolving/future landscape (SoC) Futility analysis to determine effect size & trial sample size Goal: Long/durable

benefit across sub-groups including poor prognostic population, favorable safety profile MM1636 (n=30) IOB-023 - New Proposed Adaptive Ph3 study (n=550-800) IOB-013 (n=407) IIT (NCT05912244) (n=43) IO102-IO103 in 1L ADVANCED MELANOMA |

Cylembio is at the forefront of triplet combination therapy development *Statistical significance threshold for this study was p 0.045. Source: Data on file. Comparisons across clinical trials should be interpreted with caution. Differences in

study design, patient populations, endpoints, and other factors limit the ability to draw direct or reliable conclusions between separate trials.

Primary endpoint PFS by central

review Secondary/exploratory endpoints OS, DoR, TTR, DCR Incidence of AEs and SAEs Quality of life Biomarkers in blood and tumor tissue will also be assessed Stratification Endpoints Phase 2 (step 1) Randomization Advanced melanoma Unresectable

stage III Metastatic stage IV Patients with acral or mucosal melanoma (TBD) Patients > 6 months after neoadjuvant/ adjuvant anti-PD-1 (TBD) Measurable disease (RECIST 1.1) ECOG performance status 0-1 Stable CNS disease is allowed Eligibility

criteria 1L, first-line; AE, adverse event; BLA, Biologics License Application; CNS, central nervous system; CRR, complete response rate; DCR, disease control rate; DoR, duration of response; DRR, durable response rate; ECOG, Eastern Cooperative

Oncology Group; IA, interim analysis; IDMC, independent data monitoring committee; mut, mutation; ORR, objective response rate; OS, overall survival; PD-1, programmed cell death protein 1; PFS, progression-free survival; ph, phase; q3w, once every 3

weeks; RECIST, Response Evaluation Criteria in Solid Tumors; SAE, serious adverse event; TTR, time to response; WT, wild-type. ClinicalTrials.gov: NCT05155254. *Stage III and IV M1a-b vs. stage IV M1c-d IO102-IO103 and aPD-1+LAG-3 inhibitor

N=200 aPD-1+LAG-3 inhibitor N=200 PD-L1 status Prior aPD1/aPD-L1 exposure 1:1 PROPOSED IOB-023 ADAPTIVE PHASE 3 CLINICAL TRIAL DESIGN | Leading the future triplet treatment landscape in 1L advanced melanoma @ ~150 PFS events Size of second phase to

be determined by observed HR Will also include a futility assessment Sample Size Re-estimation (expected mid 2028) Continue Enrolling Phase 3 (step 2) IO102-IO103 and aPD-1+LAG-3 inhibitor N= up to 200 additional aPD-1+LAG-3 inhibitor N= up to 200

additional 1:1 Proposed IOB-023 Clinical Trial Design Trial Initiation Subject to Raising Additional Capital

Our Pipeline: NSCLC, SCCHN,

Neoadjuvant/adjuvant

Product candidates Line of therapy/

indication Pre-clinical Phase 1 Phase 2 Phase 3 Takeaways & next steps Cylembio IO102-IO103 Targets: IDO1, PD-L1 IOB-013, IOB-023: First Line Advanced Melanoma* Cylembio demonstrated clinical improvement in PFS, narrowly

missed statistical significance in IOB-013 Potential to discuss MAA submissions based on IOB-013 with EU regulators Plan to align on IOB-023 trial design with FDA IO102-IO103 IOB-022: First Line Solid Tumors* Lung (NSCLC) Head & Neck

(SCCHN) SCCHN: Primary endpoint met NSCLC: Encouraging data IOB-032: Neoadjuvant / Adjuvant Solid Tumors* Melanoma Head & Neck (SCCHN) Enrollment completed in January 2025 Initial data available 2H25; presented in 2026 IO112 Target: Arginase 1

Solid Tumors Indications TBD Next pipeline candidate expected to enter clinical development IO170 Target: TGFb Solid Tumors Indications TBD Early-stage pipeline candidate PIPELINE | 3 T-win product candidates being evaluated in multiple cancer

indications Cylembio (imsapepimut and etimupepimut, adjuvanted) * In combination with pembrolizumab; NSCLC, non-small cell lung cancer, PFS, progression-free survival; SCCHN, squamous cell carcinoma of the head and neck; IOB-013:

ClinicalTrials.gov: NCT05155254; IOB-022: ClinicalTrials.gov: NCT05077709; IOB-032: ClinicalTrials.gov: NCT05280314 IOB-013 IOB-023 - proposed seamless phase 2/3

FIRST-LINE METASTATIC NSCLC Results

from Phase 2 (SITC 2024) ORR 55% unconfirmed/48% confirmed; mPFS 8.1 months Benchmark** ORR 39%, mPFS 6.5 months Status Encouraging ORR and PFS and no progression in nearly half of patients FIRST-LINE RECURRENT/ METASTATIC SCCHN Results from Phase 2

(ESMO 2024) ORR 44.4%; mPFS 6.6 months Irrespective of HPV status Benchmark** ORR 23%, mPFS 3.4 months Status Primary endpoint ORR met with encouraging PFS FIRST-LINE ADVANCED MELANOMA Results from Phase 3 (IOB-013): 19.4 months mPFS; HR=0.77 (CI

0.58-1.00) (p=0.056)*; narrow miss on statistical significance; demonstrated clinical improvement observed across virtually all subgroups & stratification factors; Next Steps: Plan to align on new phase 3 design with FDA & discuss submission

of MAAs based on IOB-013 data with EMA TOTALITY OF CLINICAL DATA IS COMPELLING | Clinical meaningful activity demonstrated across three indications expanding the body of evidence across three indications and settings *Statistical significance

threshold for this study was p 0.045; ** KEYNOTE-048 (pembro alone in 1L SCCHN PD-L1 CPS 20%): ORR 23%; KEYNOTE-042 (pembro alone in 1L NSCLC PD-L1 TPS 50%): ORR 39%; 1. Kjeldsen JW, et al. Nat

Med 2021;27:2212-23. Erratum in: Nat Med 2022;28:871 ; 2. Lorentzen CL, et al. J Immunother Cancer 2023;11:e006755; 3. ClinicalTrials.gov: NCT05155254; 4. Riess JW, et al. Presented at ESMO 2024.

Poster 1022P; 5. Riess JW, et al. Presented at STIC 2024. Poster 756 Starting with advanced melanoma

ADDRESSABLE PATIENTS | Cylembio

with potential to redefine treatment of hard-to-treat solid tumors and expanding beyond 1L advanced melanoma Total addressable patients (US) >100,000 patients1 ~40,000 patients2 ~15,000 patients3 Expand to earlier lines 3 Peri-operative SCCHN

Peri-operative melanoma Advance to other hard-to-treat tumors 2 1L metastatic NSCLC 1L advanced SCCHN Anchor in 1L advanced melanoma 1 1. 2025 estimated incidence of resectable Melanoma and SCCHN patients in the US . SEER; For melanoma refer to

references in footnote #3; Ko C, Citrin D. Radiotherapy for the management of locally advanced squamous cell carcinoma of the head and neck. Oral Dis. 2009 Mar;15(2):121-32.) 2. 2023 estimated 1L mSCCHN CPS>20 patients in the US. SEER; Bhat. Adv

Cancer Res. 2021; Fakhry. ACS Journals, 2018; Gallo Cancers, 2023 special issue; Placa J of Cancer Treatment and Diagnosis, 2021; Barsouk. Med Sci. 2023; Cramer. Oral Oncol. 2019; Siegel. CA Cancer J Clin. 2023; Wusiman. Pathol Res Prac. 2022;

estimated 1L addressable mNSCLC PD-L1 50%: SEER; American Cancer Society; Mack Cancer, 2020; Evans Pathology and Oncology Research, 2018; Ganti. JAMA. 2021; Rodak. Cancers. 2021; ASCO; GlobalData; NCI; Karacz. Clin Lung Cancer. 2019; Shah.