Testing the Addition of an Anti-Cancer Drug, ZEN003694, to the Usual Chemotherapy Treatment (Capecitabine) for Metastatic or Unresectable Cancers

Inclusion Criteria: * Dose Escalation additional criteria: Patients must have histologically confirmed cancer that is metastatic or unresectable and must have progressed on standard therapies which would have included fluorouracil (5-FU) or capecitabine * Dose Escalation additional criteria specifically for colorectal cancer (CRC) patients: Willingness and ability to undergo a pre-treatment biopsy * Dose Expansion additional criteria: Patients must have histologically confirmed CRC that is metastatic or unresectable and must have progressed on standard therapies which would have included 5-FU or capecitabine * Dose Expansion additional criteria: Willingness and ability to undergo pre- and on- treatment biopsies * Patients must have measurable disease * Age \>= 18 years. Because no dosing or adverse event data are currently available on the use of ZEN003694 (ZEN-3694) in combination with capecitabine in patients \< 18 years of age, children are excluded from this study * Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 (Karnofsky \>= 60%) * Availability of archival tumor tissue at the time of patient enrollment for molecular profiling studies * Prior to study dosing, previous systemic therapy must have been completed for at least five half-lives or 2 weeks, whichever is shorter * Absolute neutrophil count \>= 1,000/mcL * Platelets \>= 100,000/mcL * Total bilirubin =\< 1.5 institutional upper limit of normal (ULN) * Aspartate aminotransferase (AST) (serum gl…