Nivolumab, Fluorouracil, and Interferon Alpha 2B for the Treatment of Unresectable Fibrolamellar Cancer

Inclusion Criteria: * Patients, or their legal guardian, must give written informed consent prior to initiation of therapy, and patients under age 18 must give assent in keeping with the policies of the institution. Patients with a history of major psychiatric illness must be judged able to fully understand the investigational nature of the study and the risks associated with the therapy * Patients with histologically confirmed FLHCC (or with documentation of original biopsy for diagnosis is acceptable if tumor tissue is unavailable). The determination of resectability status will ultimately lie in the clinical judgment of the surgical oncologist and medical oncologist involved in the care of the patient. The definition of resectability is as follows: hepatectomy can achieve a negative margin while preserving more than 30% of the total estimated liver volume, sparing two contiguous hepatic segments, and maintaining vascular inflow, vascular outflow, and biliary drainage. Patients with extrahepatic disease are defined as having unresectable disease * Patient must have measurable disease defined as a lesion that can be accurately measured in at least one dimension (longest diameter to be recorded) and measures \>= 15 mm with conventional techniques or \>= 10 mm with more sensitive techniques such as magnetic resonance imaging (MRI) or spiral computed tomography (CT) scan * Eastern Cooperative Oncology Group performance status (ECOG PS =\< 1), or for patients under age 18 Karno…