Testing A New Anti-cancer Drug Combination, Entinostat and ZEN003694, for Advanced and Refractory Solid Tumors

Inclusion Criteria: * Patients must have a) advanced or refractory solid tumor and must meet standard requirements for treatment * For patients in Phase 2: Patients must have locally advanced, unresectable OR metastatic pancreatic cancer refractory to standard therapy * For patients with solid tumors, they must have measurable disease based on Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria * For patients with solid tumors, they must have received at least one standard of care regimen for metastatic disease * Age \>= 18 years. Because no dosing or adverse event data are currently available on the use of ZEN003694, alone or in combination with entinostat, in patients \< 18 years of age, children are excluded from this study * Eastern Cooperative Oncology Group (ECOG) performance status =\< 1 (Karnofsky \>= 70%) * Hemoglobin \>= 9.0 g/dL (measured within 14 days prior to administration of study treatment) * Absolute neutrophil count (ANC) \>= 1,500/mcL (measured within 14 days prior to administration of study treatment) * Platelets \>= 100,000/mcL (measured within 14 days prior to administration of study treatment) * Total bilirubin =\< 1.5 x institutional upper limit of normal (ULN) (measured within 14 days prior to administration of study treatment) * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase \[SGPT\]) =\< 2.5 x institutional ULN (measured within 1…