Inclusion Criteria:

          -  Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

          -  Have adequate organ functions as defined in the protocol

          -  Negative childbearing potential

          -  Have ability to swallow and retain oral medication and no clinically significant
             gastrointestinal abnormalities

          -  Patients with diseases for which no curative therapies are available, and who have
             progressed on at least two lines of approved therapy for their histological subtypes
             which includes an anti-PD-1 or anti-PD-L1 based therapy (as mono or combination)

          -  Disease progression on anti-PD-(L)1 based therapy (as monotherapy or combination
             therapy) and must meet criteria for acquired resistance as defined in the protocol

          -  Patients who have completely recovered from any clinically significant AEs that
             occurred during prior immunotherapy

          -  Estimated life expectancy of at least 3 months

          -  Objective evidence of disease progression at baseline (Dose Escalation)

          -  Histologically or cytologically confirmed, unresectable, locally advanced, or
             metastatic NSCLC, SCCHN, and UC (Dose Expansion)

          -  Measurable disease as per RECIST v1.1 defined as at least 1 lesion (Dose Expansion)

        Exclusion Criteria:

          -  Have experienced primary resistance to anti-PD-(L)1 based therapy

          -  Has experienced a toxicity that led to permanent discontinuation of prior anti-PD-(L)1
             based therapy or other immunotherapies

          -  Has active autoimmune disease that has required systemic treatment in the past 2 years

          -  Current use of immunosuppressive medication at time of study entry

          -  Have an active infection requiring antibiotics, antifungal or antiviral agents or have
             received a course of antibiotics within the previous 4 weeks of starting study
             treatment

          -  Has received a live vaccine within 4 weeks of starting of study treatment

          -  Known history of, or any evidence of active, non-infectious pneumonitis

          -  Prior solid organ or allogeneic stem cell transplantation

          -  Has had any investigational or anti-tumor treatment within 4 weeks or 5 half-life
             periods of starting study treatment, had any major surgeries within 4 weeks of
             starting study treatment

          -  Has received proton pump inhibitors (PPIs) within 2 weeks prior to dosing study
             treatments

          -  Has known active central nervous system (CNS) metastases and/or carcinomatous
             meningitis

          -  Has clinically significant (i.e., active) cardiovascular disease

          -  Has known history of uncontrolled intercurrent illness

          -  Has any psychiatric condition that would prohibit the understanding or rendering of
             informed consent or that would limit compliance with study requirements.