PDCD1 and cancer: Several mAbs have been approved by the US Food and Drug Administration for the treatment of various cancers, including nivolumab (anti-PD-1, Bristol Myers Squibb) for the treatment of melanoma (12) and non-small cell lung cancer [NSCLC (13)]; and atezolizumab (anti-PD-L1, Roche) for the treatment of triple-negative breast cancer (14), NSCLC (15).