A run-in phase will precede expansion, to establish basic feasibility of the nivolumab with chemoradiation schedule. The run-in cohorts will include 6 patients at each dose schedule, with 2 planned changes in dose schedule if >33% toxicity or other dose limiting toxicity (DLT) is observed. A minimum of 6 patients and maximum of 18 patients may be enrolled in the three run-in cohorts. The maximum tolerated dose (MTD) schedule will be selected when 4/6 patients at a dose schedule complete therapy without grade 3-4 immune related toxicity. All patients will receive the same dose of nivolumab (240mg).