Testing Treatment With Encorafenib and Binimetinib Before Surgery for Melanoma With Lymph Node Involvement

Inclusion Criteria: * Patient must have histologically proven melanoma that is clinically evident (macroscopic lymphadenectomy \[LAD\]) stage III B/C/D, (American Joint Committee on Cancer \[AJCC\] 8th edition) of cutaneous origin or unknown primary. Patients must have at least one clinically evident lymph node metastasis (N1c patients are not eligible). * This may be an initial presentation with primary tumor and nodal metastases or locoregional nodal relapse with history of resected primary melanoma * Stage IIIB * T0-3a N1b M0 * T1a-3a N2b M0 * Stage IIIC * T0 or T3b-4b N2b M0 * T3b-4b N1b M0 * Any T N2c M0 (at least 1 clinically evident node) * T0-4a N3b M0 * Stage IIID * T4b N3b/c M0 (if 3c: at least 1 clinically evident node) * Patient must have measurable disease on baseline imaging scans, obtained within 4 weeks prior to registration as defined by RECIST and by the following criteria * The melanoma target tumor must be completely resectable as determined by a surgical oncologist or experienced melanoma surgeon * Extensive satellitosis or in transit metastases are not considered completely resectable * Patient must have BRAF V600 mutation positive based on report from Clinical Laboratory Improvement Act (CLIA) certified laboratory * Patient must be medically fit to undergo surgery * Absolute neutrophil count (ANC) \>= 1.5 x 10\^9/L (obtained \< 14 days prior to registration) * Hemoglobin \>= 8 g/dL without transfusion (ob…