A Study to Evaluate the Safety and Therapeutic Activity of GI-102 As a Single Agent and in Combination with Conventional Anti-cancer Drugs, Pembrolizumab or Trastuzumab Deruxtecan(T-DXd) in Patients with Advanced Solid Tumors (KEYNOTE-G08)

Key Inclusion Criteria: * Males and females aged ≥ 18 years (or ≥ 19 years according to local regulatory guidelines) at the time of screening. * Has adequate organ and marrow function as defined in protocol. * Measurable disease as per RECIST v1.1. * ECOG performance status 0-1. * Adverse events related to any prior chemotherapy, radiotherapy, immunotherapy, other prior systemic anti-cancer therapy, or surgery must have resolved to Grade ≤1, except alopecia and Grade 2 peripheral neuropathy. * HIV infected patients must be on anti-retroviral therapy (ART) and have a well-controlled HIV infection/disease as defined in protocol. Key Exclusion Criteria: * Has known active CNS metastases and/or carcinomatous meningitis. * An active second malignancy. * Has active or a known history of Hepatitis B or known active Hepatitis C virus infection. * Has active tuberculosis or has a known history of active tuberculosis. * Active or uncontrolled infections, or severe infection within 4 weeks before study treatment administration. * History of chronic liver disease or evidence of hepatic cirrhosis, except patients with liver metastasis. * Has an active autoimmune disease that has required systemic treatment in past 2 years. * Previous immunotherapies related to mode of action of GI-102. * Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy or any other form of immunosuppressive medications within 2 weeks prior to Cycle 1 Day 1. * Administration of prior systemic anti-cancer therapy including investigational agents within 4 weeks prior to treatment. * Radiotherapy within the last 2 weeks before start of study treatment administration, with exception of limited field palliative radiotherapy. * Administration of a live, attenuated vaccine within 4 weeks before Cycle 1 Day 1. * Known hypersensitivity to any of the components of the drug products and/or excipients of GI-102. Other protocol defined inclusion exclusion criteria may apply