This medical study is trying out a new treatment for a type of blood cancer called acute myeloid leukemia (AML). The treatment uses special cells known as CAR-NK cells that are modified natural killer cells. These cells come from healthy donors and are designed to target and fight the cancer. Before these cells are given, patients will receive a type of chemotherapy called FC, which stands for Fludarabine and Cyclophosphamide. The study is mainly focused on patients whose cancer has returned or hasn't responded to other treatments.

• The study requires regular monitoring for safety and possible side effects.
• Participants need to be 18 or older and meet specific health conditions.
• Effective contraception is required during and after the study for safety reasons.