PDCD1 and neoplasm: used immunohistochemistry to detect the protein expression levels of m6A readers, such as YTHDF1 and YTHDF2 in 603 cases of non-small cell lung cancer tissues and evaluated four subgroups as TILs in tumor nests and surrounding stroma (PD-1, CD8, Foxp3 and CD45RO), and to study the differential expression of PD-L1 in lung cancer cells lacking YTHDF1 and YTHDF2.