CD8A and neoplasm: Clonal expansion of ccRCC-infiltrating non-exhausted CD8+ T cells and/or de novo introduction of peripherally expanded CD8+ T cells to tumor site can be a more convincing and potential mechanism underlying the immune response to ICI than the widely presumed reinvigoration of the pre-existing exhausted CD8+ T cells [44,55,62,135,137,138,160,161].