Testing the Addition of an Antibody to Standard Chemoradiation Followed by the Antibody for One Year to Standard Chemoradiation Followed by One Year of the Antibody in Patients With Unresectable Stage III Non-Small Cell Lung Cancer

Inclusion Criteria: * STEP 1 INCLUSION ELIGIBILITY CRITERIA - CONCURRENT THERAPY * Patient must be \>= 18 years old * Patient must have one of the following: * Newly diagnosed stage IIIA/B/C non-small cell lung cancer (NSCLC) (per the American Joint Committee on Cancer \[AJCC\] 8th edition) that is unresectable and is histologically and/or cytologically confirmed * Nodal recurrence after surgery for early stage NSCLC * Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Patient must have a body weight \> 30 kg * Patient must not have unintentional weight loss \> 10% within 30 days prior to registration * Patient must have a baseline electrocardiography (ECG) obtained within 6 weeks prior to registration * Patient must have measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) version (v)1.1. Baseline imaging assessments and measurements used to evaluate all measurable or non-measurable sites of disease must be done within 4 weeks prior to registration * Absolute neutrophil count (ANC) \>= 1500 cells/uL (obtained =\< 7 days prior to registration) * White blood cells (WBC) counts \>= 2500/uL (obtained =\< 7 days prior to registration) * Platelet count \>= 100,000/uL (obtained =\< 7 days prior to registration) * Hemoglobin \>= 9.0 g/dL (obtained =\< 7 days prior to registration) * Total bilirubin =\< 1.5 x institutional upper limit of normal (ULN) with the following exception: patients with known Gilbert dise…