Gene expression profiling (GEP) was conducted on baseline tumor samples from 100 Chinese patients with UC enrolled in the phase 2 tislelizumab study...MTOR and REV3L were associated with shorter PFS (P=0.02; P=0.003) and OS (P=0.03; P =0.008), respectively...high expression of tumor intrinsic genes related to angiogenesis and the mTOR pathway may indicate resistance and suggest potential future drug combinations for these patients.