Improving Early Detection of Melanoma Recurrence With Circulating Tumor DNA (ctDNA)

INCLUSION CRITERIA: * Patient must be ≥ 18 years of age. * Patient must be a surgical candidate with Stage IIB, IIC melanoma or fully resectable Stage III B/C/D cutaneous melanoma. * Patients with resectable in transit/nodal metastatic disease who have had prior adjuvant or systemic/intralesional therapy can be included provided that the planned resected lesions either progressed or developed while on or after completion of prior treatment. Patients with resectable in transit/nodal metastatic disease who are treated with neoadjuvant therapy prior to resection are also eligible provided that the initial blood and tumor biopsy sample are taken prior to initiation of neoadjuvant therapy. * Tissue available meeting one of the following criteria: 1. For patients with Clinical stage II primary tumors that have been biopsied prior to evaluation by the surgeon, or those with stage III tumors that have been partially/fully excised prior to definitive surgery, adequate tissue will be confirmed prior to enrollment to follow Natera's tissue sample collection instructions when selecting the appropriate specimen. OR 2. For patients with bulky lymph nodes involved with clinically evident, biopsy proven metastatic disease, in transit metastasis, or with extensive residual primary tumor present prior to excision, and in the treating surgeon's assessment there will be extensive tumor for evaluation, the patient can be enrolled with tissue adequacy evaluation post resection * Patient is willing to provide blood samples for Signatera testing as outlined in the study calendar. * Patient is able to provide informed consent and willing to sign an approved consent form that conforms to federal and institutional guidelines. EXCLUSION CRITERIA: * Patient is unable to provide informed consent or is unwilling to sign an approved consent form. * Patient has other clinically significant disorders that would preclude safe study participation