<p>Cellular senescence entails a state of an essentially irreversible proliferative arrest in which cells remain metabolically active and secrete a range of pro-inflammatory and proteolytic factors as part of the senescence-associated secretory phenotype. Senescent cells exhibit both anti-tumor and pro-tumor properties, contributing to the dual role they play in tumor development. Currently, cellular senescence is widely recognized as acknowledged as a robust mechanism for tumor suppression. However, many studies have also pointed out that SASP factors play a key role in tumor development and progression by affecting a variety of processes. In this review, we first summarize the characteristics of cellular senescence. We then discuss its dual roles in tumors and strategies for harnessing senescence therapy. Finally, we highlight the relationship between cellular senescence and cancer development remains a significant challenge.</p>