Inclusion Criteria:  Patient age ≥ 18 years Histologically/cytologically confirmed diagnosis of non-small-cell lung cancer (NSCLC) Patients with non-operable NSCLC in tumor stage III A/B/C after UICC 8 Eligible for platinum-based concurrent chemoradiotherapy followed by durvalumab maintenance treatment No invasive carcinoma in the last five years. ECOG Performance Status 0-2 Lung function parameters (before or after bronchodilation): FEV1 ≥ 1.0 L and/or DLCO-SB ≥ 40% A maximum of two cycles of induction chemotherapy are permissible before start of chemoradiotherapy  Exclusion Criteria:  Simultaneous participation in another clinical trial Mixed histology of small-cell and non-small-cell lung cancer Brain metastases confirmed by a contrast enhanced cMRI Prior receipt of an immunotherapy or investigational medicinal product Previous exposure to an anti-PD-1 or anti-PD-L1 antibody Pneumonitis ≥ Grade 2 as a result of prior radio-/chemoradiotherapy Patients with a non-active disease in the last 5 years can be included, but only after consultation with the responsible investigator of the study or his representative Primary immunodeficiencies in previous history Prior Interstitial lung disease (ILD) Prior autoimmune disease Previous organ transplantation with subsequent therapeutic immunosuppression