A Clinical Study of MK-8294 in Participants With Advanced Solid Tumors (MK-8294-001)

MK-8294, the study medicine, is a type of targeted therapy designed to treat certain solid tumors. The main goals of this study are to learn about the safety of MK-8294 and if people can tolerate it and find the highest dose level of MK-8294 that people can tolerate.

Inclusion Criteria: The main inclusion criteria include but are not limited to the following: * Has histologically or cytologically confirmed advanced/metastatic solid tumor; including head and neck squamous cell carcinoma, cervical squamous cell carcinoma, esophageal squamous cell carcinoma, breast cancer (triple negative breast cancer, Estrogen Receptor \[ER\]/progesterone receptor +, human epidermal growth factor receptor 2 negative \[HER2-\]), endometrial, and bladder cancer by pathology report and have previously failed standard treatment, lack standard treatment options, or are intolerant to standard treatment * Human immunodeficiency virus (HIV)-infected participants must have well controlled HIV on antiretroviral therapy (ART) * Participants who are hepatitis B surface antigen (HBsAg) positive are eligible if they have received Hepatitis B virus (HBV) antiviral therapy for at least 4 weeks, and have undetectable HBV viral load * Participants with history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable Exclusion Criteria: The main exclusion criteria include but are not limited to the following: * HIV-infected participants with a history of Kaposi's sarcoma and/or Multicentric Castleman's Disease * Has a history of New York Heart Association Class II or greater heart failure * Has received any prior immunotherapy and was discontinued from that treatment due to a Grade 3 or higher immune-related Adverse Event (irAE) (except endocrine disorders that can be treated with replacement therapy) or was discontinued from that treatment due to Grade 2 myocarditis or recurrent Grade 2 pneumonitis * Has ongoing radiation-related toxicities, requiring corticosteroids * Has known additional malignancy that is progressing or has required active treatment within the past 2 years * Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis * Has active autoimmune disease that has required systemic treatment in the past 2 years except replacement therapy (eg, thyroxine, insulin, or physiologic corticosteroid) * Has active infection requiring systemic therapy * Has history of stem cell/solid organ transplant * Has not adequately recovered from major surgery or have ongoing surgical complications