Given this complex molecular landscape, our study retrospectively evaluated BRAF gene mutations and PD-L1 expression, using qPCR and IHC, respectively, in a unique clinical setting: a high-risk bladder tumor arising during anti-BRAF/MEK therapy for concurrent MM, followed by unexpected complete spontaneous necrosis of the bladder tumor under Nivolumab immunotherapy, and subsequent relapse. The gene discussed is BRAF; the disease is Miyoshi myopathy.