found that the deletion of methyltransferases Mettl3 and Mettl14 inhibited N6 methyladenosine (m6A) mRNA modification, enhanced pMMR-MSI-L colorectal cancer and melanoma patients’ response to anti-PD-1 therapy, and significantly slowed down tumor grows and prolongs the patient’s survival. The gene discussed is METTL3; the disease is melanoma.