PDCD1 and cancer: Monoclonal antibodies (mAbs) acting as PD‐1 and PD‐L1 inhibitors are a group of immunotherapy drugs that block the interaction between PD‐1 and PD‐L1 preventing the ‘off’ signal from being transmitted and, therefore, boosting T‐cell immunity against a variety of human cancers (Gong et al., 2018; Waldman et al., 2020).