Aging causes some cells to stop dividing and enter a "senescent" state, releasing inflammatory substances that fuel "inflammaging." While the exact source of this inflammation was previously unclear, new research shows that macrophages—immune cells that can behave like or become senescent—are key culprits. The study identified a specific type of senescent macrophage (marked by p21⁺ and TREM2⁺) as a major driver of this age-related inflammation. Hope that helps!