A Study to Investigate the Effects of Durvalumab With Oleclumab Following Chemoradiation in Participants With Locally Advanced Unresectable Non-Small Cell Lung Cancer (LADOGA)

INCLUSION CRITERIA: * Participant must be ≥ 18 years at the time of screening. * Histologically-documented NSCLC and have been treated with concurrent or sequential CRT for locally advanced, unresectable (Stage III) disease. * Documented tumour PD-L1 status by qualified lab (local or central). * Documented EGFR and ALK wild-type status (local or central). * Patients must not have progressed following definitive, platinum based, concurrent or sequential chemoradiotherapy. * Participants must have received at least 2 cycles of platinum-based chemotherapy before or concurrent with radiation therapy. * Participants must have received a total dose of radiation of 60 Gy ±10% (54 Gy to 66 Gy) as part of the chemoradiation therapy, to be enrolled. Radiation therapy should be administered by intensity modulated RT/volumetric modulated arc therapy (preferred) or 3D-conforming technique. * WHO performance status of 0 or 1. * Adequate organ and marrow function. EXCLUSION CRITERIA: * History of another primary malignancy except for malignancy treated with curative intent with no known active disease ≥5 years before the first dose of study intervention and of low potential risk for recurrence, adequately resected non-melanoma skin cancer and curatively treated in situ disease, or adequately treated carcinoma in situ or Ta tumours without evidence of disease. * Mixed small cell and non-small cell lung cancer histology. * Participants with locally advanced (Stage III) unresectable NSCLC who have progressed during platinum-based CRT. * Any unresolved toxicity CTCAE \>Grade 2 from the prior chemoradiation therapy (excluding alopecia). * Participants with ≥grade 2 pneumonitis from prior chemoradiation therapy. * History of idiopathic pulmonary fibrosis, drug-induced pneumonitis, or idiopathic pneumonitis - regardless of time of onset prior to study treatment assignment. Evidence of active non-CRT induced pneumonitis (≥ Grade 2), active pneumonia, active ILD, active or recently treated pleural effusion, or current pulmonary fibrosis. * Active or prior documented autoimmune or inflammatory disorders (with exceptions). * Current or prior use of immunosuppressive medication within 14 days before the first dose of durvalumab.