CD274 and acute myeloid leukemia: A pioneer study by Yang et al. [133] showed how MDS and AML patient samples and leukemia cell lines treated with demethylating agents caused upregulation (increased expression) of the immunosuppressive ligands PD‐L1, PD‐L2, and their (immunosuppressive) checkpoint receptor PD‐1, including in vitro PD‐1 demethylation and subsequent reactivation.