USP18 and urinary bladder cancer: Ubiquitin‐specific peptidase 18 (USP18) is considered a critical multifunctional deubiquitinase that moderates the stability of key proteins to contribute to the carcinogenesis process.[43, 44] Recently, PD‐1/PD‐L1‐targeting immune checkpoint inhibitors (ICIs) have been proven to be promising treatment modalities in bladder cancer.[45, 46] Our study demonstrated that USP18 downregulation caused by BCCE4[A] could decrease the protein stability of PD‐L1, attenuate the PD‐L1/PD‐1 interaction and sensitize bladder cancer cells to T‐cell‐mediated killing.