Immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) is a life-threatening complication of chimeric antigen receptor T cell (CAR-T) therapy. Despite its high mortality rate, IEC-HS remains underrecognized due to overlapping clinical and laboratory features with severe cytokine release syndrome (CRS), leading to delayed diagnosis and suboptimal management. This review systematically analyzes key strategies to distinguish IEC-HS from severe CRS in the literatur...