IDH2 and cancer: We focused on eight draggable genes for BTC, which were described as having evidence of therapeutic impact (evidence level 2A‐3B) based on the clinical practice guidance for next‐generation sequencing in cancer diagnosis and treatment; these include ERBB2, NTRK1, RNF43, CDK6, CDKN2B, FGFR2, IDH1, and IDH2.