PDCD1 and metastatic melanoma: Recently, a failure on a phase 3 trial in metastatic melanoma, based on the combination of epacadostat (IDO1 inhibitor) with pembrolizumab (anti-PD-1 antibody), generated a disappointment in the so-called “second generation” of immuno-oncology drugs (clinical trial information: NCT02752074) (25).