 - Part 1 only: Participants with stage IIB, IIC, III, or IV melanoma at original diagnosis or at restaging after recurrence. Patients with high-risk stage IIA melanoma by DecisionDx Melanoma test, Castle Biosciences, Inc,;Friendswood, TX also may be eligible. These participants may have had cutaneous, uveal, mucosal primary melanoma, or an unknown primary melanoma. Diagnosis of melanoma must be confirmed by cytological or histological examination. Staging of cutaneous melanoma will be based on version 7 AJCC staging system. 