PDCD1 and cancer: Nivolumab stands for a human IgG4 PD‐1 immune checkpoint inhibitor antibody, which selectively counters the link between PD‐1 and its ligand (PD‐L1), promoting the action of T‐cell function.57 Although the promising role of these new drugs, there are still problems about their controversial activity, above all the different mechanisms, in which PD‐1/PD‐L1 could also be involved in different cancer types.