Avelumab With Bempegaldesleukin With or Without Talazoparib or Enzalutamide in Advanced or Metastatic Solid Tumors

Inclusion Criteria:

Participants must be ≥ 18 years old.
Participants with SCCHN or mCRCP.
Participants must have histological diagnosis of solid tumors and provide tumor tissue.
Measurable disease by RECIST v1.1 with at least 1 measurable lesion.
Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 0 or 1.
Adequate bone marrow, renal and liver function
Highly effective contraceptive use by men with the ability to father a child or women of childbearing potential.
A WOCBP must have a negative highly sensitive pregnancy test ([urine or serum] as required by local regulations) at C1D1.
Signed and dated informed consent.

Exclusion Criteria:

Known prior severe hypersensitivity to investigational products or any component in their formulations, including known severe hypersensitivity reactions to monocolonal antibodies.
Known history of: immune-mediated colitis, inflammatory bowel disease, pneumonitis, or pulmonary fibrosis.
Active or prior autoimmune disease that might deteriorate when receiving an immunostimulatory agent.
Prior organ transplantation including allogenic stem cell transplantation.
Vaccination within 4 weeks prior to C1D1 and while on trial is prohibited except for administration of inactivated vaccines.
Known symptomatic brain lesions requiring steroids.
Known history of testing positive for human immunodeficiency virus (HIV or known acquired immunodeficiency syndrome (AIDS).
Positive HBV surface antigen or HCV test indicating acute or chronic infection..
Active infection requiring systemic therapy
Clinically significant (i.e., active) cardiovascular disease including the following: documented left ventricular ejection fraction (LVEF) <50% by ECHO/MUGA; cerebral vascular accident/stroke or transient ischemic attack; myocardial infarction; unstable angina; congestive heart failure or serious cardiac arrhythmia (uncontrolled, clinically significant) requiring medication.
Diagnosis of any other malignancy within 2 years prior to C1D1, except for adequately treated basal cell or squamous cell skin cancer, carcinoma in situ of the breast, bladder or of the cervix and for Combination A only, low-grade (Gleason 6 or below) prostate cancer on surveillance with no plans for treatment intervention (e.g., surgery, radiation, or castration) or adequately treated prostate cancer.
Current use of immunosuppressive medication at the time of study enrollment.
Major surgery within 4 weeks prior to study enrollment.
Conditions that may impair intake or absorption such as inability to swallow capsules or tablets; known malabsorption syndrome; or baseline diarrhea ≤ Grade 1.
Participation in other studies involving investigational drug(s) within 2 weeks prior to C1D1.