The onset of immune checkpoints, including the expression and signaling of programmed cell death protein-1/programmed death ligand-1 (PD-1/PD-L1), is not the complete mechanism driving tumor immune evasion, and other factors, including metabolic intercommunication or competition between tumor cells and stroma [1], acidosis of the tumor microenvironment (TME) [2], hydrolysis of microenvironmental ATP [3], and tumor fibrosis [4], are also amongst the major obstacles. Here, PDCD1 is linked to neoplasm.