IL2 and hematologic disorder: Thus, to figure out the direct impact of IL-2 on the activating receptors of clinical-grade NK cells, we used primary NK cells from healthy donors expanded ex vivo using cytokines (e.g., IL-2 and IL-15) and feeder cells (K562‐mb15‐41BBL), using a protocol adopted in clinical trials for hematological malignancies and solid tumors (31–33).