A First-in-Human Open-label, Phase I/Ib Dose Escalation and Expansion Cohort Study of EOS006215 as Monotherapy and in Combination With Pembrolizumab or Other Anticancer Treatments in Participants With Advanced Solid Tumors

Inclusion Criteria:

• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

• Histologically or cytologically confirmed advanced or metastatic unresectable solidtumors for which standard approved treatment is not available or the participant isineligible or did not tolerate the standard approved treatment.

• At least one tumor lesion measurable per RECIST v1.1

• Have an estimated minimum life expectancy of ≥ 12 weeks.

• Adequate organ/marrow and liver function

• Agree to use adequate highly effective method of contraception during the study ismandatory, if WOCBP or male

Exclusion Criteria:

• Prior systemic anticancer treatment including investigational agents within 3 weeks (or 5 half-lives, whichever is shorter) before the first dose of study treatment

• Major surgery planned or within 5 weeks before the first dose of study treatment, orminor surgical procedure (except tumor biopsy) within 7 days before the first doseof study treatment.

• Radiotherapy within 2 weeks before the first dose of study treatment.

• Evidence of severe active or chronic infections requiring systemic antibacterial,antiviral, or antifungal treatment, including tuberculosis infection

• Known seropositivity for or active infection with human immunodeficiency virus (HIV)

• Known seropositivity for hepatitis B virus (HBV), with evidence of active HBVinfection

• Known seropositivity for hepatitis C virus (HCV), with evidence of active HCVinfection

• Live or live-attenuated vaccine within 30 days before the first dose of studytreatment.

• History or current evidence of uncontrolled or significant cardiovascular disease

• History or current evidence of significant autoimmune disease that required systemic

• treatment

• Diagnosis of immunodeficiency or any condition requiring systemic treatment withimmunosuppressive medication

• Pregnant or breastfeeding.