PD-1/PD-L1 and CD8 T cells are closely related, as PD-1 blockade can increase CD8 T cell and tumor-specific interferon-γ production in the tumor microenvironment [38] or produce anti-tumor effects by increasing KLRG1 + LAG3 - TNFα+ tumor-specific T cells in tumors [76]. This evidence concerns the gene KLRG1 and neoplasm.