Abstract: The present application provides compositions, methods, and kits for treating cancer, including bladder cancer such as luminal bladder cancer, using an FGFR3 inhibitor in combination with a checkpoint inhibitor. In some embodiments, the cancer expresses wild-type FGFR3. The FGFR3 inhibitor may be an antagonistic FGFR3 inhibitor, such as an antagonistic FGFR3 antibody. The checkpoint inhibitor may be a PD1 inhibitor, including a PD1 or PD1 ligand (PD-L1) antibody such as an antagonistic PD1 or PD-L1 antibody.