The goals of this clinical study are to identify if GS-4528 alone or in combination with anti-programmed cell death protein 1 (PD-1) (Anti-PD-1) Monoclonal Antibody is safe and tolerable in people with solid tumors and to identify the recommended dose of GS-4528 for further development that is safe to give to people alone or in combination with Anti-PD-1 Monoclonal Antibody. The primary objectives of this study are: * To assess the safety and tolerability of GS-4528 as monotherapy and in combination with Anti-PD-1 Monoclonal Antibody in participants with advanced solid tumors. * To identify the maximum tolerated dose (MTD)/maximum administered dose (MAD) and/or the recommended Phase 2 dose (RP2D) of GS-4528 as monotherapy and in combination with Anti-PD-1 Monoclonal Antibody in participants with advanced solid tumors.