Study Of OX40 Agonist PF-04518600 Alone And In Combination With 4-1BB Agonist PF-05082566

Inclusion Criteria:

- Part A1 only: Patients with histological or cytological diagnosis of HNSCC, HCC,
melanoma, or clear cell RCC who progressed on or are intolerant to standard therapy,
for which no standard therapy is available or who decline standard therapy.

- Part A2 only: Patients with histological or cytological diagnosis of
advanced/metastatic HCC who are treatment naïve and have declined standard of care, or
have had at least 1 prior line of systemic therapy. Prior anti PD L1/PD 1 therapy is
allowed.

- Part B1 only: Patients with histological or cytological diagnosis of NSCLC, HNSCC,
melanoma, urothelial bladder carcinoma (including renal pelvis, ureters, urinary
bladder, and urethra), gastric or squamous cell carcinoma of the uterine cervix who
progressed on or are intolerant to standard therapy, for which no standard therapy is
available, or who decline standard therapy.

- Part B2

Arm 1 only:

1. Ocular melanoma patients with advanced/metastatic disease, or

2. Cutaneous/acral melanoma patients with advanced/metastatic disease who have received
checkpoint inhibitor (anti PD L1, anti PD 1, or anti CTLA4) based treatment on which
disease progressed. [Note: Checkpoint inhibitor may have been part of a combination
therapy, as long as the combination did not contain OX40 or 4 1BB agonist.] Any
questions on prior treatment may be discussed with the Sponsor.

Arm 2 only:

- Histological or cytological diagnosis of NSCLC with advanced/metastatic disease.
Patients must have previously received prior anti PD L1 or anti PD 1 mAb on which
disease progressed. [Note: Previous anti PD L1 or anti PD 1 mAb may have been part of
a combination therapy, eg, in combination with chemotherapy, as long as the
combination did not contain OX40 or 4 1BB agonist.]

- Performance Status of 0 or 1 - Adequate bone marrow, kidney and liver function

Exclusion Criteria:

- Brain metastases requiring steroids

- Major surgery, Radiation therapy within 4 weeks of starting study treatment (except:
palliative radiotherapy to a limited field is allowed after consultation with
sponsor's medical monitor at any time during study participation, including during
screening), or systemic anti-cancer therapy within 4 weeks of study treatment start (6
weeks for mitomycin C or nitrosoureas)

- Active and clinically significant bacterial, fungal, or viral infection

- History of active autoimmune disorders

- History of immune-mediated adverse events requiring immunosuppressive therapy or were
grade 3 or higher related to prior immune-modulatory therapy

- Prior treatment with an OX40 agonist and 4-1BB agonist (for Part B1/B2)

- Prior anthracycline treatment and at risk of cardiac failure (New York Heart
Association Class 2)