Anti-PD-1 antibody exerts anticancer activity by blocking the binding of PD-1 on T cells to PD-L1 on tumor cells to reinvigorate T cell-mediated antitumor immunity2, whose clinical effectiveness is highly associated with tumor immunosuppressive microenvironment and the extent of CD8+ T cell infiltration into tumors7,8. Here, CD8A is linked to neoplasm.