An Investigational Study of CX-2051 in Participants With Advanced 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 * 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 * Systemic anticancer treatment, radiotherapy, or investigational agent(s) within 14 days prior to C1D1 * Previous treatment with antibody-drug conjugates (ADCs) with Topo-I inhibitor payload * Major surgery (requiring general anesthesia) within 4 weeks prior to C1D1 * Elevated baseline laboratory values * Serious concurrent illness * Pregnant or breast feeding * Additional exclusion criteria may apply