The Purpose of This Research Study is to See if Combining Gemcitabine, Cisplatin and Durvalumab Chemotherapy Treatments With a Direct Tumor Therapy Yittrium-90 (Y-90) Will Work Better Together to Shrink Tumors and Control Cancer

Gemcitabine 1000 mg/m2, Cisplatin 25 mg/m2 infused on both day 1 and day 8 of a 21-day cycle. Durvalumab 1500 mg will be given on day 1 of each cycle.

Patients will undergo a Y-90 treatment planning consultation by the treating interventional radiologist during cycle 1. One or two cycles (depending on tumor size) of cisplatin, 25 mg/m2 and gemcitabine 300 mg/m2 given on day 1 and day 8 in combination with Yttrium-90 (Y-90) microspheres which will be given on day 3-7 or day 10-21 at the discretion of the interventional radiologist, separated in time by at least 2 days from a chemo infusion during that cycle

Gemcitabine 1000 mg/m2 and Cisplatin 25 mg/m2 given on days 1 and 8 of a 21-day cycle with durvalumab 1500 mg given on day 1 of each cycle for 3-5 additional cycles. For the cycle directly after Y-90, gemcitabine will be kept at a dose of 300 mg/m2 to minimize risk of toxicity.