This is an open-label, Phase 1/2 study to evaluate the safety of durvalumab (MEDI4736) in combination with oxaliplatin/capecitabine chemotherapy in metastatic/locally advanced oesophageal cancer (OC) and with neoadjuvant chemo(radio)therapy before surgery in operable OC. The immunotherapy will be given for a 4-week period before starting the standard chemo(radio)therapy, continuing durvalumab treatment once the chemotherapy starts. The study will include 2 phases, a safety run-in Phase 1 (Cohorts A1 and A2) and an expansion Phase 2 (Cohorts B, C, and D).