In BTCs, especially intrahepatic cholangiocarcinoma, comprehensive molecular profiling has expanded precision oncology through actionable alterations such as <i>FGFR2</i> rearrangements, <i>IDH1</i> mutations, <i>HER2</i> amplification/overexpression, <i>BRAF</i> V600E, <i>NTRK</i> fusions, and MSI-high/dMMR status. The gene discussed is IDH1; the disease is intrahepatic cholangiocarcinoma.