Tumor microbiota research is a new field in oncology. With the advancement of high-throughput sequencing, there is growing evidence that a microbial community exists within tumor tissue. How these bacteria access tumor cells varies, including through the invasion of mucous membranes, the bloodstream, or the gut-organ axis. Previous literature has shown that microbes promote the development and progression of cancer through various mechanisms, such as affecting the host's immune system, promoting inflammation, regulating metabolism, and activating invasion and transfer. The study of the tumor microbiota offers a new perspective for the diagnosis and treatment of cancer, and it holds the potential for the development of new diagnostic tools and therapies. The role of the tumor microbiota in the pathogenesis of cancer is becoming increasingly evident, and future research will continue to uncover the specific mechanisms of action of these microbes, potentially shedding light on new strategies and methods for cancer prevention and therapy. This article reviews the latest advancements in this field, including how intratumor microbes migrate, their carcinogenic mechanisms, and the characteristics of different types of tumor microbes as well as the application of relevant methods in tumor microbiota research and the clinical values of targeting tumor microbes in cancer therapy.