Cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and programmed cell death 1 (PD1) receptor inhibit antitumour immunity through complementary and non-redundant mechanisms. A new trial assessed the combination of ipilimumab (a CTLA4-specific monoclonal antibody) and nivolumab (a PD1-specific monoclonal antibody) in 142 patients with metastatic melanoma who had not previously received treatment. The patients were randomly assigned to receive either ipilimumab and nivolumab or ipilimumab alone. The primary end point of this study specifically addressed patients with BRAF wild-type melanoma, as no high responses to BRAF inhibitors have been reported in these patients, and therefore their options are limited. Among these patients, objective response was 61% in the combination group versus 11% in the ipilimumab-monotherapy group (P < 0.001), and response in patients with BRAF mutations was similar (52% versus 10%). Progression-free survival was not reached in patients receiving the combination therapy and was 4.4 months in patients receiving only ipilimumab. More toxic effects were reported in the combination group (54% versus 24% of patients). In addition, as melanoma commonly metastasizes to the myocardium, overly vigorous responses in that area could cause myocardial damage with grave consequences.