PD-L1-IN-7 (compound CB31) is an inhibitor of PD-L1 , which can induce PD-L1 internalization and PD-L1 retention in cells. PD-L1-IN-7 can inhibit the interaction of PD-1/PD-L1 ( IC 50 : 0.2 nM), change the glycosylation pattern, and promote PD-L1 degradation. PD-L1-IN-7 can also enhance T cell infiltration, amplify T cell function and the ability to kill tumor cells.