CD8A and neoplasm: Of them all, the presence of tumor-infiltrating CD8+ T cells, which recognize tumor antigens, is a prerequisite for successful ICI treatment when presented at the tumor cell surface in the context of HLA class I. Several small-sized studies and a meta-analysis demonstrated that CD8+ TILs were significantly associated with better OS, PFS, and ORR in NSCLC patients treated with ICIs [52,53,54,55,56,57,58].