This phase II trial studies how pembrolizumab works before and after surgery in treating patients with stage III-IV high-risk melanoma. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body’s immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Giving pembrolizumab before and after surgery may work better in treating melanoma. Eligibility includes being at least 18 years old and:
•Patients must have resectable melanoma in order to be eligible for this study. Patients must have clinically detectable stage III (clinically detectable N1b, N1c, N2b, N2c, N3b and N3c) or stage IV resectable melanoma.
•Patients are eligible for this trial either at initial presentation of their melanoma or at the time of the first detected nodal, satellite/in-transit, distant metastases, or recurrent disease
