All in all, we observed the occurrence of urothelial bladder carcinoma, concurrent with the initiation of anti-BRAF/MEK chemotherapy, and its progression under this treatment, suggesting a possible causal role for BRAF/MEK inhibitors in the carcinogenesis of urothelial carcinoma, followed by complete spontaneous tumor necrosis under Nivolumab, and then tumor recurrence post-necrosis, under the same immunological treatment, implicitly claiming the establishment of some occult mechanism of resistance to immunotherapy. The gene discussed is BRAF; the disease is neoplasm.