Specific mechanism: SAM promotes m6A modification of PD-L1 mRNA in tumor cells, and the specific binding protein YTH structural domain family protein 1 (YTHDF1) recognizes and binds to m6A-modified PD-L1 mRNA and promotes PD-L1 expression, methionine dietary restriction or targeting of YTHDF1 enhances the therapeutic effects of PD-L1 blockade (46). Here, CD274 is linked to neoplasm.