CCR7 and neoplasm: Upon tumor neoantigen stimulation, naive CD8+ T cells (characterized by upregulated expression of CCR7, LEF1, TCF7, and SELL) or memory CD8+ T cells (characterized by high levels of ZNF683) are activated, subsequently proliferating and differentiating into effector CD8+ T cells (also called cytotoxic lymphocytes) to recognize and kill tumor cells (5, 14, 20).