A Trial to Find Safe and Active Doses for an Investigational Drug, CX-904, for Patients With Advanced Solid Tumors

Inclusion Criteria: * Histologically confirmed metastatic or locally advanced unresectable solid tumor. Must have received prior standard therapy. * Measurable disease per RECIST 1.1 * Eastern Cooperative Oncology Group performance status of 0 or 1 * Adequate baseline laboratory values * Patients of childbearing potential or those with partners of childbearing potential must agree to use a highly effective method of birth control from signing the ICF, and for a period of 30 days after the last dose of CX-904. * Additional inclusion criteria may apply Exclusion Criteria: * History of malignancy that was active within the previous 2 years. Exceptions include localized cancers that are not related to the current cancer being treated, that are considered to have been cured, and in the opinion of the Investigator, present a low risk of recurrence * Screening electrocardiogram demonstrating a mean QTcF value \> 480 msec; a screening echocardiogram with left ventricular ejection fraction (LVEF) \< 50% * Serious concurrent illness * History of or current active autoimmune diseases * History of myocarditis regardless of the cause * Pregnant or breast feeding * Additional exclusion criteria may apply