Cancer is a predominant cause of mortality worldwide, necessitating the development of innovative therapeutic techniques. The human microbiome, particularly the gut microbiota, has become a significant element in cancer research owing to its essential role in sustaining health and influencing disease progression. This review examines the microbiome's makeup and essential functions, including immunological modulation and metabolic regulation, which may be evaluated using sophisticated methodologies such as metagenomics and 16S rRNA sequencing. The microbiome influences cancer development by promoting inflammation, modulating the immune system, and producing carcinogenic compounds. Dysbiosis, or microbial imbalance, can undermine the epithelial barrier and facilitate cancer. The microbiome influences chemotherapy and radiation results by modifying drug metabolism, either enhancing or reducing therapeutic efficacy and contributing to side effects and toxicity. Comprehending these intricate relationships emphasises the microbiome's significance in oncology and accentuates the possibility for microbiome-targeted therapeutics. Contemporary therapeutic approaches encompass the utilisation of probiotics and dietary components to regulate the microbiome, enhance treatment efficacy, and minimise unwanted effects. Advancements in research indicate that personalised microbiome-based interventions, have the potential to transform cancer therapy, by providing more effective and customised treatment alternatives. This study aims to provide a comprehensive analysis of the microbiome's influence on the onset and treatment of cancer, while emphasising current trends and future possibilities for therapeutic intervention.