Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related mortality worldwide. Immune checkpoint inhibitors targeting the PD-1/PD-L1 and CTLA-4 axes have fundamentally transformed its treatment landscape. This narrative review traces the evolution of NSCLC immunotherapy, from advanced-stage monotherapy and chemoimmunotherapy to its critical expansion into early-stage disease, highlighting the paradigm shift brought by neoadjuvant, adjuvant, and perioperative strategies. We examine essential clinical challenges, including optimal treatment duration, management of brain metastases, immune-related adverse events, and mechanisms of primary and acquired resistance, with a focus on genomic alterations like KRAS co-mutations with STK11 and KEAP1 . Furthermore, we critically evaluate the evolving biomarker landscape, moving beyond PD-L1 to encompass circulating tumour DNA, microbiome composition, and multiparametric approaches like T-cell receptor clonality. Finally, we provide an in-depth exploration of next-generation strategies, including bispecific antibodies, novel checkpoint targets, mRNA vaccines, antibody-drug conjugates, and advanced cellular therapies. While significant progress has been made, refining biomarker-driven selection and optimizing combination sequencing remain paramount. This thorough synthesis highlights promising future directions to overcome these hurdles and improve long-term survival in NSCLC.

MET inhibitors have shown promising efficacy for MET-dysregulated non-small cell lung cancer (NSCLC). However, quite a few patients cannot benefit from it due to the lack of powerful biomarkers. This study aims to explore the potential role of plasma proteomics-derived biomarkers for patients treated with MET inhibitors using mass spectrometry. We analyzed the plasma proteomics from patients with MET dysregulation (including MET amplification and MET overexpression) treated with MET inhibitors. Thirty-three MET-dysregulated NSCLC patients with longitudinal 89 plasma samples were included. We classified patients into the PD group and non-PD group based on clinical response. The baseline proteomic profiles of patients in the PD group were distinct from those in the non-PD group. Through protein screening, we found that a four-protein signature (MYH9, GNB1, ALOX12B, HSD17B4) could predict the efficacy of patients treated with MET inhibitors, with an area under the curve (AUC) of 0.93, better than conventional fluorescence in situ hybridization (FISH) or immunohistochemistry (IHC) tests. In addition, combining the four-protein signature with FISH or IHC test could also reach higher predictive performance. Further, the combined signature could predict progression-free survival for MET-dysregulated NSCLC (p < 0.001). We also validated the performance of the four-protein signature in another cohort of plasma using an enzyme-linked immunosorbent assay. In conclusion, the four plasma protein signature (MYH9, GNB1, ALOX12B, and HSD17B4 proteins) might play a substitutable or complementary role to conventional MET FISH or IHC tests. This exploration will help select patients who may benefit from MET inhibitors.