In recent years, the incidence of tumors has shown an increasing trend, while traditional treatment methods such as surgery, radiotherapy, and chemotherapy exhibit certain limitations. Immunotherapy has been extensively investigated in the field of cancer treatment due to its advantages of high specificity in recognition, significant inhibition of tumor growth and proliferation, and the absence of adverse effects on the structure and function of normal tissue cells. Natural killer (NK) cells, as crucial components of the innate immune system, play a pivotal role in antitumor immune responses. In this study, a magnetic nanocarrier loaded with NK cells was constructed to combine magnetic targeting with NK immunotherapy. By integrating magnetic targeting with NK cell immunotherapy, this system enhances NK cell infiltration at tumor sites through external magnetic field guidance, thereby improving the tumor-killing efficacy. The main research contents are as follows: nanoscale Fe