Inclusion Criteria:  Age ≥ 18 years. Measurable disease per disease-specific response criteria. Patients must have disease that is metastatic or unresectable and have received standard treatment options, are not candidates for standard treatment options, or will otherwise be prevented from receiving any standard treatment options. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. Minimum of 3 weeks or 5 half-lives (whichever is shorter) since last dose of systemic cancer therapy (unless otherwise specified) or minimum of 2 weeks since last radiotherapy, or minimum of 6 weeks since last systemic therapy with nitroureas, antibody-drug conjugate, or radio immuno-conjugate therapy. Adequate organ and bone marrow function, in the absence of growth factors, as defined by laboratory parameters. Patients of child-bearing potential must use adequate contraceptive measures to avoid pregnancy for the duration of the study as defined in the protocol. Patient must be willing and able to adhere to the prohibitions and restrictions specified in the protocol. Each patient must sign an informed consent form (ICF). Histological or cytological diagnosis of platinum-resistant EOC, including primary peritoneal and fallopian tube carcinoma; gastric/GEJ cancer; HNSCC; metastatic or unresectable melanoma; NSCLC; mCRPC; MPM; TNBC; locally advanced or metastatic urothelial cancer; cervical cancer; MSS CRC; or DLBCL-RT (Phase 1b only). Accessible tumor or lymph node (e.g., DLBCL-RT) for biopsy (Phase 1b only).  Exclusion Criteria:  Active untreated brain metastases.  Patient has any of the following:  Uncontrolled intercurrent illness including, but not limited to, poorly controlled hypertension or diabetes, or ongoing active infection requiring systemic therapy. History of known or suspected seizure disorder. Patients with primary refractory EOC defined as patients who do not respond to their first platinum-containing regimen or who relapse less than 6 months after completion of that first platinum-containing regimen. Psychiatric illness or social situation that would limit compliance with study requirements. Prior treatment with a CPI (anti-PD-1, PD-L1, CTLA-4, etc.) within 3 weeks prior to the first dose of study drug. History of chimeric antigen receptor T-cell (CAR-T) therapy within 100 days prior to the first dose of study drug. Must have evidence of B-cell recovery if prior CAR-T therapy. Toxicities from previous anti-cancer therapies that have not resolved to baseline levels or to Grade 1 or less except for Grade 2 alopecia and Grade 2 peripheral neuropathy. Patients who experienced Grade 3 or higher irAEs with prior immunotherapy. History of uveitis, or an active autoimmune disease that has required systemic treatment in the past 2 years (i.e., with use of disease modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment and is allowed. Unable to swallow capsules or has malabsorption syndrome, disease significantly affecting gastrointestinal function, or resection of the stomach or small bowel or ulcerative colitis, symptomatic inflammatory bowel disease, or partial or complete bowel obstruction likely to interfere with the delivery, absorption, or metabolism of study drug. Known allergies, hypersensitivity, or intolerance to components of study drug. Pregnant, breastfeeding, or planning to become pregnant while enrolled in this study or within 6 months after the last dose of study drug. Patient is a man who plans to father a child while enrolled in this study or within 3 months after the last dose of study drug. Patient has had major surgery (e.g., requiring general anesthesia) within 4 weeks before the planned first dose of study drug, or will not have fully recovered from surgery, or has surgery planned during the time the patient is expected to participate in the study or within 4 weeks after the last dose of study drug. Note: Patients with minor planned surgical procedures to be conducted under local anesthesia may participate. Vaccinated with a live vaccine within 28 days (with the exception of the annual inactivated influenza vaccine) prior to the first dose of study drug.  Active known second malignancy with the exception of any of the following:  Adequately treated basal cell carcinoma, squamous cell carcinoma of the skin, or in situ cervical cancer. Adequately treated Stage I cancer from which the patient is currently in remission and has been in remission for ≥ 2 years. Low-risk prostate cancer with Gleason score < 7 and PSA < 10 ng/mL. Any other cancer from which the patient has been disease-free for ≥ 2 years. Infection with human immunodeficiency virus (HIV)-1 or HIV-2. Exception: Patients with well controlled HIV (e.g., CD4 > 350/mm3 and undetectable viral load) are eligible. Current active liver disease from any cause, including hepatitis A (hepatitis A virus immunoglobulin M [IgM] positive), hepatitis B (hepatitis B virus [HBV] surface antigen positive), or hepatitis C (hepatitis C virus [HCV] antibody positive, confirmed by HCV RNA). Patients with HCV with undetectable virus after treatment are eligible. Patients with prior exposure to HBV may be entered if quantitative PCR is negative. Use of systemic corticosteroids (> 20 mg prednisone or equivalent) within 15 days (except for prophylaxis for radio diagnostic contrast reactions), or other immunosuppressive drugs within 30 days, prior to the first dose of study drug. Use of biotin (i.e., Vitamin B7) or supplements containing biotin higher than the daily adequate intake of 30 µg [NIH 2020] (Note: Patients who switch from a high dose to a dose of 30 µg/day or less at least 1 day prior to Screening assessments are eligible for study entry). Receipt of an investigational product (IP) or has been treated with an investigational device within 3 weeks or 5 half-lives (whichever is shorter) prior to the first dose of study drug.  Any of the following within 6 months prior to the first dose of study drug:  Myocardial infarction Unstable angina Unstable symptomatic ischemic heart disease New York Heart Association Class III or IV heart failure Thromboembolic events (e.g., deep vein thrombosis, pulmonary embolism, or symptomatic cerebrovascular events) Any other significant cardiac condition (e.g., pericardial effusion, restrictive cardiomyopathy, severe untreated valvular stenosis, or severe congenital heart disease) Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the study, interfere with the participant's participation for the full duration of the study, or is not in the best interest of the participant to participate, in the opinion of the treating Investigator Use, within 14 days prior to the first dose of study drug, or the need for concomitant treatment with, a potent or moderate inhibitor or inducer of CYP3A4 or sensitive P glycoprotein substrate.