We next examined the effect of OTUB2-IN-1 on PD-L1 degradation, and found that OTUB2-IN-1 was able to reduce the PD-L1 level in tumor cells in a dose-dependent manner, but it failed to affect the stability of OTUB2 (Fig. 9f and Supplementary Fig. 20a−c). Here, OTUB2 is linked to neoplasm.