Cytokines drive the formation of memory-like NK cell subsets via epigenetic rewiring and transcriptional regulation.

Activation of natural killer (NK) cells with the cytokines interleukin-12 (IL-12), IL-15, and IL-18 induces their differentiation into memory-like (ML) NK cells; however, the underlying epigenetic and transcriptional mechanisms are unclear. By combining ATAC-seq, CITE-seq, and functional analyses, we discovered that IL-12/15/18 activation results in two main human NK fates: reprogramming into enriched memory-like (eML) NK cells or priming into effector conventional NK (effcNK) cells. eML NK cells had distinct transcriptional and epigenetic profiles and enhanced function, whereas effcNK cells resembled cytokine-primed cNK cells. Two transcriptionally discrete subsets of eML NK cells were also identified, eML-1 and eML-2, primarily arising from CD56 ^bright or CD56 ^dim mature NK cell subsets, respectively. Furthermore, these eML subsets were evident weeks after transfer of IL-12/15/18-activated NK cells into patients with cancer. Our findings demonstrate that NK cell activation with IL-12/15/18 results in previously unappreciated diverse cellular fates and identifies new strategies to enhance NK therapies.