PDCD1 and melanoma: For instance, 64–70% of patients with advanced BRAFV600-mutant melanoma respond to combination BRAF/MEK inhibitors with median overall survival (OS) of 22–34 months compared to the BRAF inhibitor vemurafenib alone (objective response rate (ORR) of up to 50% and median OS of ∼17 months).6, 7, 8 Immunotherapies targeting the immune inhibitory receptors cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death 1 (PD-1) enhance T cell-mediated anti-tumour responses.