Carbon-based nanozymes (CNs) have emerged as a significant innovation in targeted cancer therapy, demonstrating great potential for advancing cancer diagnosis and treatment. With exceptional catalytic properties, remarkable biocompatibility, and the ability to precisely target cancer cells, CNs provide a promising avenue for the development of novel oncological therapies. By functionalizing their surfaces with targeting ligands, such as antibodies or peptides, CNs can specifically recognize and bind to cancer cells. This targeted approach ensures that therapeutic agents are delivered directly to the tumor site, minimizing off-target effects, and reducing systemic toxicity. Additionally, the enzyme-like activities of CNs, when combined with conventional therapies such as chemotherapeutics, photothermal therapy, and photodynamic therapy, or other modalities can enhance therapeutic outcomes. Integrating CNs into clinical practice could significantly improve therapeutic efficacy, reduce probable side effects, enhance patient outcomes, and drive a shift towards more personalized cancer care. Besides, CNs can also be employed in biosensors and diagnostic nanomaterials, enabling rapid, selective, and highly accurate detection of specific biomarkers. Their versatile functionalities open new avenues for refining imaging techniques, ultimately contributing to early diagnosis and better clinical decision-making. This review consolidates recent studies exploring CNs in cancer targeting, highlighting both their diagnostic and therapeutic potential in oncology.