PDCD1 and melanoma: Led by the UK National Cancer Research Institute Skin Cancer Clinical Studies Group, DANTE randomizes patients with unresectable stage III or stage IV melanoma who have received 1 year of PD-1 blockade without having their disease progress to either (1) stopping treatment (with the option to restart anti-PD-1 therapy or commence other treatment on progression) or (2) continuing treatment for another year or until disease progression/unacceptable toxicity.