Fungal dysbiosis is increasingly recognized as a key factor in cancer, influencing tumor initiation, progression, and treatment outcomes. This review explores the role of fungi in carcinogenesis, with a focus on mechanisms such as immunomodulation, inflammation induction, tumor microenvironment remodeling, and interkingdom interactions. Fungal metabolites are involved in oncogenesis, and antifungals can interact with anticancer drug, including eliciting potential adverse effects and influencing immune responses. Furthermore, mycobiota profiles have potential as diagnostic and prognostic biomarkers, emphasizing their clinical relevance. The interplay between fungi and cancer therapies can impact drug resistance, therapeutic efficacy, and risk of invasive fungal infections associated with targeted therapies. Finally, emerging strategies for modulating mycobiota in cancer care are promising approaches to improve patient outcomes.