PDCD1 and cancer: These inhibitory drugs targeting immune checkpoints, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and its ligand (PD-L1), can bring long-lasting clinical benefits by eliciting immune responses against tumors in the treatment of various cancer entities (Bagchi et al., 2021).