Inclusion Criteria:

• Age 18 or older.
• In the dose-escalation phase: histologically- or cytologically- confirmed advanced solid tumor that is refractory to standard therapy and for which no standard therapy exists.
• In the dose-expansion phase: histologically- or cytologically- confirmed advanced solid tumor where if an approved first-line therapy is available, subjects must have failed, be intolerant to, be ineligible for, or have refused
• Eastern Cooperative Oncology Group (ECOG) status of 0 or 1.
• Adequate organ and marrow function.
• Subjects must have at least 1 measurable lesion.
• Available archived tumor tissue sample.
• Willingness to provide consent for biopsy sample (dose-expansion only)

Exclusion Criteria:

• Any prior Grade ≥ 3 irAE while receiving immunotherapy
• Prior exposure to any anti-PD-1 or anti-PD-L1 antibody
• Any concurrent chemotherapy, immunotherapy, biologic or hormonal therapy for cancer treatment.
• Prior treatment with immunotherapy agents including, but not limited to, tumor necrosis factor receptor superfamily agonists or checkpoint inhibitors or natural killer (NK) cell inhibitors.
• Active or prior documented autoimmune disease within the past 2 years
• History of primary immunodeficiency
• History of organ transplant that requires use of immunosuppressives
• Symptomatic or untreated central nervous system (CNS) metastases requiring concurrent treatment
• Other invasive malignancy within 2 years
• Women who are pregnant or lactating
• Uncontrolled intercurrent illness
• Known history of tuberculosis
• Known to be human immunodeficiency virus (HIV) positive
• Known to be Hepatitis B or C positive (except HCC patients)