USP8 and cancer: To identify whether DUB inhibitors are involved in regulating the expression of the immune checkpoint protein PD-L1 and the efficacy of PD-1/PD-L1 blockade-based cancer immunotherapy, we screened a panel of DUB inhibitors and discovered that the USP8 inhibitor, DUBs-IN-2, but not other DUB inhibitors we examined, dramatically elevated PD-L1 protein abundance in different cancer cell lines (Fig. 1a and Supplementary Fig. 1a).