Aging is a universal biological process that leads to degenerative pathologies and cancer in vertebrates. Cellular senescence, a stress response that halts cell proliferation, is a key mechanism for tumor suppression but also contributes to both degenerative and hyperplastic pathologies, likely through chronic inflammation. Senescence is driven by various factors, including telomere shortening, genomic damage, and mitogenic signals. Senescent cells secrete the SASP, a complex of pro-inflammatory and pro-tumorigenic factors that can promote tissue repair or exacerbate age-related diseases. While senescence helps prevent cancer by halting cell division, it can also contribute to aging and cancer progression by promoting inflammation and tissue dysfunction. The SASP has dual roles, supporting tissue repair while also driving pathological processes. Senescent cells may be cleared by the immune system, but their accumulation with age and in age-related pathologies suggests a complex interplay between senescence, inflammation, and tissue repair. Research indicates that senescence plays a critical role in aging and cancer, with both beneficial and detrimental effects depending on context. Understanding senescence is essential for developing interventions to combat aging-related diseases.Aging is a universal biological process that leads to degenerative pathologies and cancer in vertebrates. Cellular senescence, a stress response that halts cell proliferation, is a key mechanism for tumor suppression but also contributes to both degenerative and hyperplastic pathologies, likely through chronic inflammation. Senescence is driven by various factors, including telomere shortening, genomic damage, and mitogenic signals. Senescent cells secrete the SASP, a complex of pro-inflammatory and pro-tumorigenic factors that can promote tissue repair or exacerbate age-related diseases. While senescence helps prevent cancer by halting cell division, it can also contribute to aging and cancer progression by promoting inflammation and tissue dysfunction. The SASP has dual roles, supporting tissue repair while also driving pathological processes. Senescent cells may be cleared by the immune system, but their accumulation with age and in age-related pathologies suggests a complex interplay between senescence, inflammation, and tissue repair. Research indicates that senescence plays a critical role in aging and cancer, with both beneficial and detrimental effects depending on context. Understanding senescence is essential for developing interventions to combat aging-related diseases.