Background <p>Natural killer (NK) cells serve as pivotal effector cells within the innate immune system, playing an indispensable role against infections and tumors. Individuals with diminished NK cell activity or NK cell deficiency are at a higher risk of developing cancers and experiencing severe viral infections. With global demographic shifts toward aging populations, elucidating the mechanisms of immunosenescence becomes increasingly critical for developing targeted therapeutic interventions against age-related disorders.</p> Main body of the abstract <p>This review provides a comprehensive summary of the phenotypic characteristics, functional changes, and mechanisms of NK cells in aging and diseases. By synthesizing current research, it highlights key pathways contributing to NK cell immunosenescence in the elderly and explores potential strategies to preserve or restore their cytotoxic and immunoregulatory functions.</p> Short conclusion <p>The review provides novel insights into NK cell immunosenescence and proposes innovative approaches to enhance NK cell activity in aging individuals, offering potential therapeutic avenues for mitigating age-related immune decline.</p>