KLRK1 and neoplasm: To date, only a few clinical studies evaluated NK92, PB-NK and UCB-NK based CAR-NK cell products with increasing interest in some commonly tumor targeted antigens such as Roundabout homolog 1 (ROBO1), NK cells activating receptor (NKG2D), MSLN, HER2 and MUC1 are registered in ClinicalTrials.gov and summarized in Table 3.