The following keywords and Boolean operators (“AND”, “OR”) were used for the narrative review: “IDH1 mutant cholangiocarcinoma,” “Cholangiocarcinoma,” “Ivosidenib OR Tibsovo,” and “Ivosidenib OR Tibsovo AND Cholangiocarcinoma” (Table 1). The gene discussed is IDH1; the disease is cholangiocarcinoma.