A First-in-Human Study of EOS301984 as Monotherapy or Combination Therapy in Adult Participants With Advanced Solid Tumors

INCLUSION CRITERIA * Provide a signed written informed consent before any study-specific evaluation. * Be at least 18 years old on the day of signing informed consent. * Have a histologically confirmed advanced solid tumor for which no standard approved treatment is available, or are ineligible for, or did not tolerate standard approved treatment. * Have at least one tumor lesion measurable per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. * Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Have adequate organ and marrow function. * Agree to use adequate highly effective method of contraception during the study is mandatory, if Women of Childbearing Potential (WOCBP) or male. EXCLUSION CRITERIA * Have received prior systemic anticancer treatment including investigational agents within 4 weeks before the first dose of study treatment. * Have major surgery planned or have had a major surgery within 5 weeks before the first dose of the study treatment. * Have received prior radiotherapy within 2 weeks before the first dose of study treatment. * Have allergy to study treatment(s) or any of its components. * Have a history or current evidence of uncontrolled or significant cardiovascular disease. Unable to comply with the requirements of the study or who, in the opinion of the Investigator, should not participate in the study. * Pregnant or breastfeeding women.