Key Inclusion Criteria:  Part A: Adults ≥ 18 years of age; Part B: ≥ 12 to years of age, weighing at least 40 kg (total body weight) Histologically-diagnosed locally advanced (unresectable), or metastatic solid cancer that has progressed after all available standard therapy for the specific tumor type, or for which all available standard therapy has proven to be ineffective or if no further standard therapy exists. Part A: Adults 18+: Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1; Part B: Adolescents ≥ 12 to < 16 years of age: Lansky Play Scale ≥ 50; Adolescents ≥ 16 years of age: Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1; Life expectancy ≥ 12 weeks Part A: Patients without RECIST measurable disease (e.g., evaluable disease only) will be eligible for enrollment in Part A, regardless of tumor type; Part B: Patients enrolled in Part B must have measurable disease by per RECIST 1.1 and have ≥ 1 site of measurable disease that has not been previously irradiated.  Key Exclusion Criteria:  Females who are pregnant (positive serum pregnancy test within 7 days prior to study drug administration) or breastfeeding.  Immune Related Medical History:  Active autoimmune disease that has required systemic disease-modifying or immunosuppressive treatment within the last 2 years Receipt of systemic immunosuppressive therapy (e.g. steroids) within 4 weeks prior to the start of study drug administration History of idiopathic pulmonary fibrosis, interstitial lung disease, organizing pneumonia, non-infectious pneumonia that required steroids, or evidence of active, non-infectious pneumonitis History of Grade ≥ 3 immune-mediated toxicity Prior allogeneic or autologous bone marrow transplant, or other solid organ transplant.  History of a positive test for:  Hepatitis C virus (HCV) infection, except for those who have completed curative therapy for HCV and have undetectable HCV RNA Hepatitis B virus (HBV) infection, except for those who are receiving treatment with HBV-active nucleos(t)ide antiviral therapy at the time of study entry and have undetectable HBV DNA Human Immunodeficiency Virus (HIV) infection, except those who meet the following criteria: CD4+ T cells ≥ 350 cells/μL, no history of Acquired Immunodeficiency Syndrome (AIDS)-defining opportunistic infections, HIV RNA < 50 copies/mL, and on a stable antiretroviral regimen for at least 3 months. Prior radiation therapy with an inadequate washout between the last dose and the start of study drug, defined as follows: 1) at least 2 weeks for palliative radiation to the extremities for osseous bone metastases is required; 2) at least 4 weeks for radiation to the chest, brain, or visceral organs is required; and 3) at least 6 weeks for large-field radiation is required. Prior anticancer therapy, including chemotherapy, targeted therapy, biological therapy or immune-checkpoint inhibitors within 4 weeks or 5 drug half-lives (whichever is shorter) History of another malignancy in the previous 2 years, unless cured by surgery alone and continuously disease free. Recent history of cardiovascular disease Uncontrolled or symptomatic CNS (central nervous system) metastases and/or carcinomatous meningitis