Fecal microbiota transplantation (FMT) has emerged as a promising approach to enhance the efficacy of tumor immunotherapy, particularly with immune checkpoint inhibitors (ICIs). This review highlights the role of gut microbiota in modulating anti-tumor immune responses and clinical outcomes. FMT, which involves transferring donor fecal microbiota to recipients, can alter the gut microbiome, regulate microbial metabolites, and reshape the tumor microenvironment (TME), thereby improving the effectiveness of ICIs. However, concerns about the long-term safety of FMT, including the risk of transmitting pathogenic microorganisms and unknown disease-causing genes, necessitate rigorous donor screening and careful evaluation of risks and benefits. Studies have shown that specific gut microbiota, such as Akkermansia muciniphila and Faecalibacterium prausnitzii, are associated with better responses to ICIs. FMT has demonstrated potential in improving anti-PD-1 and anti-PD-L1 therapies in melanoma and other cancers. Clinical trials have reported that FMT can enhance the efficacy of immunotherapy by increasing the diversity of gut microbiota, promoting the activation of CD8+ T cells, and modulating immune responses. However, the optimal microbiota composition for different tumor types remains unclear, and further research is needed to identify the most effective microbial profiles for enhancing immunotherapy outcomes. Despite its potential, FMT faces challenges such as the need for comprehensive donor screening, the complexity of the gut microbiome, and the variability in response among patients. The delivery routes of FMT, including enema, endoscopy, and oral capsules, must be carefully evaluated to ensure therapeutic efficacy and safety. Future research should focus on optimizing FMT as a combined therapy with immunotherapy, improving donor screening, and understanding the long-term effects of FMT on the gut microbiome and tumor microenvironment. Overall, FMT offers a promising avenue for enhancing tumor immunotherapy, but further studies are needed to address the current limitations and ensure its safe and effective application.Fecal microbiota transplantation (FMT) has emerged as a promising approach to enhance the efficacy of tumor immunotherapy, particularly with immune checkpoint inhibitors (ICIs). This review highlights the role of gut microbiota in modulating anti-tumor immune responses and clinical outcomes. FMT, which involves transferring donor fecal microbiota to recipients, can alter the gut microbiome, regulate microbial metabolites, and reshape the tumor microenvironment (TME), thereby improving the effectiveness of ICIs. However, concerns about the long-term safety of FMT, including the risk of transmitting pathogenic microorganisms and unknown disease-causing genes, necessitate rigorous donor screening and careful evaluation of risks and benefits. Studies have shown that specific gut microbiota, such as Akkermansia muciniphila and Faecalibacterium prausnitzii, are associated with better responses to ICIs. FMT has demonstrated potential in improving anti-PD-1 and anti-PD-L1 therapies in melanoma and other cancers. Clinical trials have reported that FMT can enhance the efficacy of immunotherapy by increasing the diversity of gut microbiota, promoting the activation of CD8+ T cells, and modulating immune responses. However, the optimal microbiota composition for different tumor types remains unclear, and further research is needed to identify the most effective microbial profiles for enhancing immunotherapy outcomes. Despite its potential, FMT faces challenges such as the need for comprehensive donor screening, the complexity of the gut microbiome, and the variability in response among patients. The delivery routes of FMT, including enema, endoscopy, and oral capsules, must be carefully evaluated to ensure therapeutic efficacy and safety. Future research should focus on optimizing FMT as a combined therapy with immunotherapy, improving donor screening, and understanding the long-term effects of FMT on the gut microbiome and tumor microenvironment. Overall, FMT offers a promising avenue for enhancing tumor immunotherapy, but further studies are needed to address the current limitations and ensure its safe and effective application.