We developed a syngeneic transplantable murine bladder cancer model using the MB49 cell line engineered to express FGFR3 with either the activating G370C mutation (FGFR3-G370C), a kinase-dead mutation K508M (FGFR3-K508M)...Tumors from mice inoculated with MB49-FGFR3-G370C cells showed diminished CD8+ T cell accumulation within the tumor and were resistant to anti-PD-L1 checkpoint blockade…