Inclusion Criteria:

          -  Must weigh at least 35 kilograms (kg).

          -  An Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2.

          -  Life expectancy of ≥ 12 weeks.

          -  Laboratory values meeting protocol criteria.

          -  QT interval corrected for heart rate < 470 msec (using Fridericia's correction), and
             no clinically significant electrocardiographic findings.

          -  Measurable disease defined by RECIST 1.1 criteria.

        For Monotherapy and Combination Dose Escalation:

        • Subjects with histologically or cytologically proven metastatic or locally advanced
        tumors, for which no effective standard therapy exists, or where standard therapy has
        failed. Subjects must have received at least 1 prior systemic anticancer therapy for the
        indication being considered.

        For Monotherapy Dose Expansion only:

          -  Subjects must have received 1 prior line containing PD-1/PD-L1 targeted therapy with a
             best response of CR/PR/stable disease by RECIST v1.1 for greater than 6 months; AND

          -  Must have been previously treated with 1 or more prior lines of therapy in the locally
             advanced or metastatic setting with the following tumor types:

               -  Relapsed/refractory HNSCC

               -  Relapsed/refractory NSCLC

               -  Advanced ccRCC

        For Combination Dose Expansion only:

          -  Subjects with gastric or GEJ adenocarcinoma whose tumors express PD-L1 (CPS ≥1)

          -  Must not have received a PD-1/PD-L1 targeting agent, or other immune-oncology agents
             as part of a prior line of therapy;

          -  Must have received, and progressed on, at least 2 prior lines of chemotherapy in the
             locally advanced or metastatic setting; •. If tumor is HER2/neu positive, subject must
             have received prior treatment with an approved HER2 targeting therapy.

        Exclusion Criteria:

          -  Untreated brain or meningeal metastases (i.e., subjects with history of metastases are
             eligible provided they do not require ongoing steroid treatment and have shown
             clinical and radiographic stability for at least 28 days after definitive therapy)

          -  Unresolved Grade 2 or higher toxicities related to previous anticancer therapy except
             alopecia.

          -  Unresolved Grade 2 or higher peripheral neuropathy.

          -  History of hepatitis B, hepatitis C, or human immunodeficiency virus (HIV) infection.

          -  Recent history (within 6 months) of congestive heart failure (defined as New York
             Heart Association, Class 2 or higher), ischemic cardiovascular event, pericarditis, or
             clinically significant pericardial effusion or arrythmia.

          -  Recent history (within 6 months) of Childs-Pugh B or C classification of liver
             disease.

          -  History of clinically significant medical and/or psychiatric conditions or any other
             reason that, in the opinion of the investigator, would interfere with the subject's
             participation in this study or would make the subject an unsuitable candidate to
             receive study drug.

          -  History of uncontrolled, clinically significant endocrinopathy.

          -  Known gastrointestinal disorders making absorption of oral medications problematic;
             subject must be able to swallow capsules.

          -  If treated with a PD-1/aPD-L1 targeting or other immune-oncology agents in the past,
             excluded if had prior pneumonitis, prior Grade 3 or higher immune mediated toxicity,
             hypersensitivity to administered drug or drug related toxicity requiring
             discontinuation.

          -  Active autoimmune disease requiring systemic treatment in past 2-years (exceptions for
             endocrinopathies, vitiligo or atopic conditions).

          -  History of solid organ transplant or allogeneic stem cell transplant.

          -  History of other malignancy, with the following exceptions:

               -  No known active disease present for ≥ 3 years before first dose of study
                  treatment and felt to be at low recurrence by investigator.

               -  Adequately treated non-melanoma skin cancer or lentigo maligna without evidence
                  of disease.

               -  Adequately treated carcinoma in situ without evidence of disease.

          -  History of interstitial lung disease or pneumonitis.

          -  Major surgery ≤ 28 days prior to first dose of study drug

          -  Known active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection
             per local testing practices.