An Investigational Study of CX-801 as Monotherapy and in Combination With PD1 Inhibition in Participants With Solid Tumors

Inclusion Criteria: * Metastatic or locally advanced unresectable solid tumor that has progressed after standard therapy * Eastern Cooperative Oncology Group (ECOG) performance status of 0-1 * Measurable disease per RECIST v1.1 * Consent to fresh biopsy or if medically contraindicated, recent (within 6 months) archival tumor tissue * Adequate organ function * Additional inclusion criteria may apply Exclusion Criteria: * Recent history (within last 2 years) of localized cancers that are not related to the current cancer being treated * Known active central nervous system (CNS) involvement by malignancy * Prior PD-1/ PD-(L)1 inhibitor treatment discontinued due to grade 3 or higher immune related adverse event * Systemic anticancer treatment within 4 weeks or 5 half lives prior to first dose of study treatment * Investigational drug or device within 4 weeks prior to first dose of study treatment * Radiation within 2 weeks prior to first dose of study treatment * Serious concurrent illness * Pregnant or breast feeding * Additional exclusion criteria may apply