The role of microbiome in immunotherapy: Insights and perspectives

The intricate interplay between the gut microbiome and the host immune system has been recognized as a pivotal determinant of clinical outcomes in cancer immunotherapy. Mounting evidence suggests that specific microbial communities are associated with both the efficacy and toxicity of immune checkpoint inhibitors in diverse malignancies, underscoring the microbiome's role in modulating systemic and tumour-localized immunity. Mechanistically, the microbiome shapes antitumour immunity by affecting antigen presentation, activation of effector cells, immunosuppression and adverse effects. Key microbial components and metabolites present in distinct anatomical niches have been identified as promoters or inhibitors of therapeutic responsiveness via multiple pathways. Harnessing this knowledge, microbiome-targeted strategies such as antibiotic, probiotic, fecal microbiota transplantation, and dietary modulation are regarded as potential adjuvant therapies to enhance the efficacy of anti-tumour therapies. Although significant progress has been achieved in preclinical studies, challenges persist in translating these findings into standardized clinical applications.