Recent clinical studies combining tyrosine kinase inhibitors of the VEGFR pathways with PD-1 checkpoint inhibitors have also shown promising clinical benefit in patients with metastatic renal cell carcinoma (RCC).41,42 However, the disease mechanism of RCC is drastically different from mucosal melanoma, and axitinib is an approved monotherapy in RCC. The gene discussed is PDCD1; the disease is mucosal melanoma.