Abstract: Extranodal NK/T cell lymphoma (ENKTL) is a rare subtype of extranodal non-Hodgkin lymphoma (NHL) with strong invasiveness. Although the chemotherapy regimen based on asparaginase is the standard treatment for advanced patients, the prognosis needs to be improved. Moreover, treatment options are limited for recurrent or refractory patients who have failed chemotherapy. In recent years, the research progress of the programmed cell death receptor-1 (PD-1)/programmed cell death ligand-1 (PD-L1) immune checkpoint inhibitor has provided a new perspective for ENKTL treatment. This article summarizes the role of PD-1/PD-L1 in the pathogenesis of ENKTL and the regulatory factors of PD-L1 expression. It also explores the differences in the PD-1/PD-L1 expression in ENKTL of different molecular typing systems as well as the application prospects of their inhibitors in the treatment of ENKTL.