Harnessing the Gut Microbiota to Improve Cancer Immunotherapy: Focus on Lung Cancer

The gut microbiota has emerged as a key orchestrator of systemic immunity, capable of reshaping the tumor microenvironment and modulating responses to cancer immunotherapy via the gut-lung axis. While immune checkpoint blockade (ICB) has revolutionized lung cancer treatment, a significant proportion of patients fail to respond. Accumulating evidence suggests that intestinal microbial composition modulates antitumor immunity, yet clinical associations between specific microbial taxa and ICB outcomes often show inconsistencies across cohorts. In this review, we synthesize current mechanistic insights into how gut microbial metabolites and structural components modulate pulmonary immune surveillance. We critically examine the clinical landscape of microbiome signatures in non-small cell lung cancer (NSCLC), highlighting how species- and strain-level heterogeneity contributes to divergent findings. Finally, we discuss translational strategies-ranging from fecal microbiota transplantation to rationally designed bacterial consortia and engineered probiotics-and propose a roadmap for integrating multi-omics with microbiome engineering to overcome current limitations and optimize precision immunotherapy.