PDCD1 and cancer: Successful clinical trials with PD-1/PD-L1 monoclonal antibodies have opened new avenues in cancer immunology, and recent FDA approved PD1 pathway inhibitors are including monoclonal antibody nivolumab (anti-PD1; Bristol-Myers Squibb), pembrolizumab (anti-PD1; Merck), atezolizumab (anti-PD-L1; Genentech/Rothe), avelumab (anti-PD-L1; EMD Serono/Merck&Pfizer) and durvalumab (anti-PD-L1; AstraZeneca).