This study included advanced non-squamous NSCLC patients without EGFR mutations or ALK rearrangements (EGFR/ALK-) treated with first-line pembrolizumab monotherapy between 2016 and 2020 (mono-IO cohort, n = 442) or first-line pembrolizumab plus chemotherapy between 2017 and 2020 (chemo-IO cohort, n = 915) within the real-world CGDB (Fig. 1a). Here, ALK is linked to non-small cell lung carcinoma.