These findings provide a compelling rationale for developing novel therapeutic strategies aimed at targeting both the IL-2 and PD-1/PD-L1 pathways without compromising GVL activity as a means to prevent GVHD [92].Through advanced genetic code expansion techniques, researchers have successfully developed IL-2 variants that covalently bind to IL-2Rα, including L72-FSY and its polyethylene glycol-conjugated form, PEG-L72FSY. The gene discussed is IL2; the disease is graft versus host disease.