The blockade of inhibitory immune checkpoints, including programmed cell death-1 (PD-1) and its ligand programmed cell death ligand-1 (PD-L1), lymphocyte activation gene-3 (LAG-3), and cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4), can reactivate the body’s immune system, thereby preventing the escape of tumor cells (Wei et al., 2018; He and Xu, 2020). Here, PDCD1 is linked to neoplasm.