PDCD1 and neoplasm: For defining tumor-infiltrating lymphocytes (TILs), six CD8+ T cell subsets (CD8-01 to CD8-06) were identified, including proliferative (T.pro), exhausted (T.ex), effector (T.eff), residential memory (T.rm), and naïve (T.na), given their specific expression of Mki67, Pdcd1, Gzmb, Klrd1, Il2rb, and Tcf7 genes, respectively.