Once IL‐2 binds to its high‐affinity receptor (IL‐2Rα/β/γc), it triggers intracellular signaling via JAK–STAT, PI3K‐Akt, and MAPK pathways which lead toT‐cell proliferation, regulatory T cell (Treg) maintenance that is essential for immune tolerance and prevention of autoimmunity, memory T‐cell formation that supports long‐term immune responses, and cytotoxic T cell (CTL) and NK cell activation. The gene discussed is IL2; the disease is Autoimmunity.