The article reviews the role of fungi in tumorigenesis, highlighting the increasing attention to the associations between fungi and human cancer. Fungi, which inhabit various anatomical sites in the human body, have been found to be enriched in patients with malignant tumors. The review discusses cancer type-specific fungal profiles and the mechanisms by which fungi influence tumorigenesis, including interactions with host immunity and bioactive metabolites. It also explores the factors that lead to the enrichment of fungi in tumor tissues and the conversion of commensal fungi to pathogenic fungi. Additionally, the article summarizes potential therapeutic and preventive strategies based on intratumoral fungi, such as diet, fecal microbiota transplantation (FMT), probiotics, and prebiotics. The review concludes by addressing several key questions that remain in the field, emphasizing the need for further research to understand the mechanisms of fungi-mediated tumor development and to explore new opportunities for cancer therapy and diagnosis.The article reviews the role of fungi in tumorigenesis, highlighting the increasing attention to the associations between fungi and human cancer. Fungi, which inhabit various anatomical sites in the human body, have been found to be enriched in patients with malignant tumors. The review discusses cancer type-specific fungal profiles and the mechanisms by which fungi influence tumorigenesis, including interactions with host immunity and bioactive metabolites. It also explores the factors that lead to the enrichment of fungi in tumor tissues and the conversion of commensal fungi to pathogenic fungi. Additionally, the article summarizes potential therapeutic and preventive strategies based on intratumoral fungi, such as diet, fecal microbiota transplantation (FMT), probiotics, and prebiotics. The review concludes by addressing several key questions that remain in the field, emphasizing the need for further research to understand the mechanisms of fungi-mediated tumor development and to explore new opportunities for cancer therapy and diagnosis.