PDCD1 and neoplasm: Recently, immunotherapy using antibodies that block the PD-1/PD-L1 pathway have shown impressive clinical outcomes with durable tumor regression and improved patient survival [1–3,  21], leading to several PD-1 antibodies (such as nivolumab and pembrolizumab) and PD-L1 antibodies (such as atezolizumab, durvalumab and BMS-936559) in clinical use or in late-stage clinical development [23].