Prognostic and predictive value of PD-L1 expression and tumour infiltrating lymphocytes (TiLs) in locally advanced NSCLC treated with simultaneous radiochemotherapy in the randomized, multicenter, phase III German Intergroup lung Trial (GILT)

•Tumor biopsies from the multicenter German Intergroup Lung Trial of radiochemotherapy followed by consolidation chemotherapy were available for PD-L1 and TiL analysis.•Tumor PD-L1 expression did not correlate with progression free survival or overall survival following RTCT for inoperable stage III NSCLC.•Tumor infiltrating lymphocyte (TiLs) score correlated with longer overall survival following RTCT for inoperable stage III NSCLC, in particular for patients treated with consolidation chemotherapy.•TiL score and TiL pattern did not correlate with differences in progression free survival. Immune checkpoint inhibition after radiochemotherapy (RTCT) has become a new standard of care for locally advanced non-small cell lung cancer with programmed death-ligand 1 (PD-L1) expression. However, little is known about the prognostic role of immune response markers in this setting. We analysed PD-L1 expression and tumour infiltrating lymphocytes (TiLs) in tumour biopsies from the multicenter German Intergroup Lung Trial (GILT), which previously randomised patients with stage III NSCLC to RTCT with or without consolidation chemotherapy. We retrospectively analyzed tumour biopsies from patients treated in the GILT trial. PD-L1 expression was analysed using the Ventana SP263 assay and TiL score (low, intermediate, high) and pattern (excluded, inflamed, desert) were assessed. The primary endpoint of the biomarker analysis was PFS in patients with PD-L1 ≥ 1% vs. PD-L1