Courtney Cavalieri, PharmD, BCOP, and Kenneth Tham, PharmD, BCOP, discuss how pharmacists play a crucial role in managing biliary tract cancer patients by providing expertise on biomarker testing, treatment selection between targeted therapies like FGFR and HER2 inhibitors, developing monitoring protocols for unique toxicities such as hyperphosphatemia, and educating patients on side effect management to optimize treatment outcomes in this rare cancer type.