PDCD1 and T-cell non-Hodgkin lymphoma: Targeting epigenetic remodeling is a potential therapeutic strategy for developing immunotherapy.17 Recently, chidamide was found to exhibit a novel mechanism of action that synergizes with humanized PD-1 antibody to enhance T-cell chemokine expression and augment IFN-γ response in NK-T cell lymphoma compare with romidepsin.18 This may be one of the main mechanisms of epigenetic drugs have synergistic antitumor effects with PD-1 monoclonal antibodies in ENKTL.