Part 1 - Signed and dated institutional review board (IRB)/ independent ethics committee (IEC)-approved informed consent form (ICF) - Has solid malignancies that have received all available standard therapies for the specific tumor type or for which no standard therapy exists, unless patient is intolerant of treatment - Has a life expectancy of ≥ 3 months - Has evaluable disease based on RECIST v1.1 - Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 - Has adequate organ function - Negative serum or urine pregnancy test for female patients of childbearing potential - Agreement to use appropriate precautions to avoid pregnancy, unless the patient and/or their sole sexual partner is permanently sterilized

Part 1 - Past or current immune-related adverse events (irAEs) due to anti-programmed cell death protein 1 ligand 1 (PD[L]1) therapy that meet any of the following criteria: 1. Grade ≥ 3 2. Resulted in discontinuation of anti-PD(L)1 therapy - Medical history of an autoimmune or inflammatory disease requiring immunosuppressive therapy - Medical history of adrenal insufficiency - Has had any major surgery within 4 weeks prior to the first dose of study treatment - Concurrent treatment with mifepristone or another glucocorticoid receptor (GR) modulator - Unable to swallow, retain, or absorb oral medication - Concurrent participation in another interventional clinical trial - Has toxicities due to prior therapies that are reversible and have not resolved - Requirement for treatment with prohibited medications, including but not limited to systemic corticosteroids and cytochrome P450(CYP)3A inducers or inhibitors - Has a known history of severe hypersensitivity to any of the study drugs, or other human/humanized monoclonal antibodies - Pregnant or lactating patients or female patients expecting to conceive children within the projected duration of the trial - Has clinically significant uncontrolled condition(s) which, in the opinion of the Investigator, may confound the results of the trial or interfere with the patient's safety or participation - Known psychiatric disorder that would interfere with trial compliance - Has infection with HIV, hepatitis C virus, or hepatitis B virus - Has untreated parenchymal brain metastasis or has uncontrolled central nervous system metastases - Has a history of another malignancy within 2 years prior to study treatment, unless cured - Has received prior autologous or allogeneic organ or tissue transplantation - A QTcF interval >450 msec, a family history of long QT syndrome or unexplained sudden death at young age, or a requirement for use of medication that may prolong the QTc interval