For more information regarding BMS clinical trial participation, please visit www.BMSStudyConnect.com Inclusion Criteria: - Histopathologic confirmation of the following tumor types (please refer to protocol for full details pertaining to eligible tumor types): 1. Merkel Cell Carcinoma 2. Gastric or Gastro-Esophageal junction carcinoma (No longer enrolling this tumor type) 3. Nasopharyngeal Carcinoma 4. Squamous cell carcinoma (SCC) of the cervix, vagina, or vulva 5. Squamous cell carcinoma of the Head and Neck 6. Squamous cell carcinoma of the anal canal and penis 7. Recurrent/metastatic SCC of the cervix not amenable to curative treatment with surgery and/or radiation therapy who are unsuitable for platinum-based therapy may enroll in the cervical cancer Combination B expansion cohort - Measurable disease by CT or MRI - Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 - Patient willing to comply to provide tumor tissue (archival or fresh biopsy specimen) - Men and women of age 18 or older Exclusion Criteria: - Active brain metastases or leptomeningeal metastases - Patients with active, known or suspected autoimmune disease - Patients with a condition requiring systemic treatment with either corticosteroids or other immunosuppressive medications - Patients with hepatitis - Patients with HIV - Pregnant or breastfeeding women