Determining Whether Durvalumab in Combination With Radiation Therapy Can Prevent the Progression of Non-Small Cell Lung Cancer

The purpose of this study is to see if Durvalumab and radiation therapy can delay the worsening of disease in patients with non-small cell lung cancer normally treated with sequential chemotherapy followed by radiation therapy.

Inclusion Criteria: * Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol. Written informed consent and any locally required authorization obtained from the patient/legal representative prior to performing any protocol-related procedures, including screening evaluations. * Patient age \>/= 18 at time of consent * Newly diagnosed or recurrent Locally-advanced NSCLC (stage II-III) amenable for treatment with concurrent definitive radiation and durvalumab * Ineligible for resection and concurrent CRT as determined by one of the following reasons: Medically inoperable, surgically unresectable (including N3 nodal disease), medically unfit or unsafe for chemotherapy, or other reason deemed appropriate by the investigator and approved by PI. Note: The reason a patient is deemed ineligible for concurrent CRT must be documented (i.e. hearing impairment, neuropathy, renal dysfunction, symptomatic/advanced underlying medical comorbidities, etc.) * Histological and/or cytological confirmation of NSCLC (both squamous and adenocarcinoma) as per standard of care biopsy; no additional research protocol-specific biopsy is needed. * ECOG/WHO PS 0-2 * Candidates for definitive RT to 60 Gy in 30 fractions * Body weight \> 30kg * Adequate normal organ and marrow function as defined below: * Hemoglobin \>/= 9.0 g/dL * Absolute neutrophil count (ANC) 1.5 x (\>/= 1500 per mm3) * Platelet count \>/= 75 x 10\^9/L (\>/= 75,000 per mm3) * Serum bilirubin \