Testing the Combination of the Anticancer Drug Durvalumab With Chemotherapy (Gemcitabine and Cisplatin) at Improving Outcomes for High-Risk Resectable Liver Cancer Before Surgery

Inclusion Criteria: * Patients must have histologically or cytologically confirmed intrahepatic cholangiocarcinoma (iCCA) that is resectable by imaging evaluation. Choice of staging modality is left up to the discretion of the treatment team; we favor high-quality CT scan of the chest/abdomen/pelvis with liver or biliary protocol. Eligibility will be confirmed through central imaging review. * Patients must have measurable disease, defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded for non-nodal lesions and short axis for nodal lesions) as \>= 10 mm (\>= 1 cm) with CT scan, MRI, or calipers by clinical exam. * Patients must be an acceptable risk surgical candidate at the time of enrollment, as determined by a board-certified surgeon with expertise in hepatobiliary surgery. * High-risk iCCA is defined as the presence of any of these factors: * Tumor size \> 5 cm. * Multifocality or satellitosis limited to the same lobe. * Vascular invasion. * Suspected or confirmed (via biopsy) regional lymph node metastases. * Suspected is defined as lymph nodes that are deemed suspicious for metastasis based on large size (criteria vary per anatomical location; 6-10 mm for abdominal and 8-10 mm for pelvic), enhancement pattern, and shape. These may also include lymph nodes that display fludeoxyglucose F 18 (FDG)-avidity on positron emission tomography (PET) scan, if obtained, in the course of disease work-u…