Effective and safe treatment options are lacking for some cancer entities. One promising approach is activation of immune cells. First clinical trials using natural killer (NK) cells show promising anti-cancer results and reduced adverse effects. However, these transferred NK cells have heterogenous functionality and subset distribution. So far, laboratory protocols to generate only highly functional and mature NK cells are lacking. This study uses a novel NK precursor able to generate these specific NK cells to study their developmental requirements. Results from this study can help future treatment of cancer patients as well as result in new knowledge about NK cell development, which paves a first step towards more specialized NK cell-based therapies.