Synthetic biology is an emerging scientific discipline that has been revolutionizing various fields of biomedicine including cancer therapy. Mimicking natural conditions, therapeutic interventions will be adopted to modify cells and increase their resilience to pro-cancerous conditions within a tumor microenvironment. Immunotherapy against cancer has been advanced through breakthroughs in synthetic biology. There appears to be great potential, especially with Chimeric Antigen Receptor T cell (CAR-T cell) treatments, combined engineering of T cells and checkpoint inhibitors, and the establishment of artificial immunomodulating pathways employing RNA. Pre-clinical studies and clinical trials have demonstrated significant potential for synthetic biology-based interventions in cancer treatment. Despite the safety issues and regulatory challenges in the widespread adoption of synthetic biology approaches for cancer treatment, the field does hold a lot of potential in its therapeutics. The basic concepts of synthetic biology, such as genetic circuit design, modular synthesis, CRISPR technology, their biomedical applications, and mechanisms of action concerning cancer interventions, are explored in this chapter. Moreover, the interesting area of bacterial-based anticancer therapies has been discussed, including targeting strategies and their representative examples.