Human cell division cycle-associated 8 (CDCA8), also known as Borealin or Dasra-B, is a critical component of the vertebrate Chromosomal Passenger Complex (CPC). It plays a pivotal role in the segregation of sister chromatids during the cell cycle and is essential for preventing the formation of aneuploid chromosomes and ensuring successful cytokinesis. Numerous studies have demonstrated that CDCA8 is upregulated in various cancers, including hepatocellular carcinoma, lung cancer, glioma, and bladder cancer. By influencing key biological processes such as cell proliferation, apoptosis, invasion, and metastasis, CDCA8 drives tumor progression. Clinically, the expression of CDCA8 correlates closely with tumor staging and histological grading, providing significant prognostic value for patients with diverse cancers. Moreover, CDCA8 modulates tumor biology through multiple signaling pathways, including P53, PI3K/Akt, E2F/Rb, and mTOR. In summary, CDCA8 represents a promising diagnostic and therapeutic target across multiple cancer types and serves as a potential prognostic biomarker. This review highlights the critical roles of CDCA8 in cancer diagnosis, treatment, and prognosis, as well as the underlying mechanisms through which it exerts its effects. These insights offer a theoretical basis and research direction for early cancer diagnosis, targeted therapy, and prognostic evaluation.