Epigenetic drugs can synergize with other cancer therapies by modulating the metabolic and pathological characteristics of cancer cells, immune cells, and stromal cells within the TME.830 Although immune checkpoint inhibitors (ICIs), which target immune checkpoint proteins (ICPs), such as PD-L1, PD-1, and CTLA-4, show significant potential, their effectiveness may be limited by factors such as insufficient antigen presentation and suboptimal T cell responses in the TME.831,832 Epigenetic modifications can enhance the expression of tumor antigens and ICPs, overcoming these limitations. This evidence concerns the gene PDCD1 and cancer.