To date, the major beneficiaries of MAb-based ICI therapy are patients with advanced melanoma (ipilimumab alone or with a PD-1 inhibitor) and NSCLC (PD-1/ PD-L1), with these malignancies appearing to be particularly responsive to this type of immunotherapy and associated with durable responses in ~25% of patients (25, 26). Here, PDCD1 is linked to melanoma.