This study is designed to explore the safety and efficacy of natural killer (NK) cell infusion as treatment for patients with advanced malignant tumors after multiline therapy, and to evaluate the pharmacokinetics of NK cells in patients

Inclusion Criteria:

1. Patients with advanced malignant tumors diagnosed by pathological histology and/or cytology who have failed multi-line therapy and have no standard treatment method are unable to undergo surgery, radiation therapy, or chemotherapy;
2. Age 18-75 years old (≥18, ≤75);
3. ECOG: 0-1;
4. Priority should be given to the inclusion of ovarian cancer, malignant leukemia, lymphoma, etc. that have been shown to respond well to NK cell therapy;
5. Expected survival period ≥ 3 months;
6. Hematology tests also meet the following requirements:

1) WBC≥3×109/L, ANC≥1.5×109/L, Hb≥90g/L, PLT≥100×109/L; 2) TBIL ≤ 1.5 × ULN (normal upper limit), ALT and AST ≤ 2 × ULN (if there is liver metastasis, then ≤ 5 × ULN); 3) Endogenous creatinine clearance ≥ 60 ml/min (calculated based on Cockcroft-Gault formula); (7) Length of solid tumors do not exceed 6 cm; (8) Signing of informed consent from each patient

Exclusion Criteria:

1. History of other malignancies with a disease-free period <5 years (except for cured basal cell carcinoma of the skin, cured carcinoma of the cervix in situ, and gastrointestinal tumors proven to be cured by endoscopic mucosal resection);
2. Patients with brain metastases (unless the investigator believes that brain metastasis is currently stable, it is generally not recommended for enrollment);
3. Transplant recipients;
4. T-cell lymphoma patients;
5. Allergies to biologics used in this treatment;
6. Patients with HIV and syphilis;
7. HBV carriers;
8. Patients who are undergoing radiation therapy or immunotherapy within 4 weeks;
9. Patients who have undergone high-dose radiation therapy on the lung and liver within 4 months;
10. Patients with pulmonary inflammation determined by chest radiography;
11. Oxygen saturation ≤ 90% on room air;
12. Patients with cachexia caused by advanced tumors;
13. Long-term use of immunosuppressive drugs or patients who are using immunosuppressive drugs;
14. Those with serious autoimmune diseases;
15. Patients with organ failure (grade 4 of heart function; liver function with Child class C or above; brain metastasis with disturbance of consciousness; severe respiratory failure symptoms);
16. Active infections (including intra-abdominal infections).
17. Researchers consider it inappropriate to participate in the trial