Preoperative Radiotherapy and Immunotherapy for Sinonasal and Anorectal Mucosal Melanoma

To determine the rate of pathologic response (\<50% viable tumor or \>50% fibrosis) for non-metastatic sinonasal melanoma patients having surgical resection after receiving neoadjuvant combination immunotherapy followed by radiation therapy. To determine the rate of pathologic response (\<50% viable tumor or \>50% fibrosis) for non-metastatic anorectal melanoma patients receiving neoadjuvant intent combination immunotherapy followed by radiation therapy.