Senolytics vs. senomorphics

Senotherapeutics are therapeutics strategies that target cellular senescence. These strategies can work by killing senescent cells (senolytics), inhibiting the proinflammatory secretory phenotype of senescent cells (senomorphics) or by activating our endogenous senolytic systems (immune surveillance). But what even are senescent cells, how do senolytics work, and what current human clinical trials provide supporting data?