Demethylation of the PD-1 promoter on T cells by 5-azacytidine in AML patients correlated with increased PD-1 expression, leading to the rational combination of DNMT inhibitor with anti-PD-1 mAbs, which are currently tested in clinical trials of NSCLC patients, but also of other cancers (86). Here, PDCD1 is linked to cancer.