This is a single arm, open-label, multi-center, Phase 1 study to determine safety and tolerability of an experimental therapy called NKX101 (allogeneic CAR NK cells targeting NKG2D ligands) in patients with relapsed/refractory AML or intermediate, high and very high risk relapsed/refractory MDS. Here, KLRK1 is linked to myelodysplastic syndrome.