FGFR2 mutations are known to occur after treatment with FGFR inhibitors as a mechanism of acquired resistance in CCA; of particular note are FGFR2, N549K, and N549H mutations, which have been reported to occur after treatment with pemigatinib and futibatinib [36, 37]. The gene discussed is FGFR2; the disease is cholangiocarcinoma.