PDCD1 and cancer: PD-1 (programmed cell death protein 1) and CTLA-4 (cytotoxic T-lymphocyte-associated protein 4) immune checkpoint inhibitors may represent a new era and a paradigm shift in cancer therapy, but, even so, the consensus is that targeted agents are not only here to stay [19] but will continue to play a significant role in combination with chemo and immunotherapy.