CD8A and neoplasm: In addition, the deficiency of MettL3 or Mettl14 in tumors results in enhancing cytotoxic tumor-infiltrating CD8+ T cells, and increasing the secretion of IFN-c, Cxcl9 and Cxcl10 in TME in vivo, which proves that the immune system and tumor microenvironment have metastasized in tumor m6A mRNA.