Inclusion Criteria:
* With inoperable advanced malignant solid tumors, including melanoma, gastrointestinal tumor, breast cancer, pancreatic cancer, cervical cancer, lung cancer, etc.
* Failed in standard treatment or voluntarily give up other treatment, and been longer than 2 weeks from the end of the last anti-tumor treatment
* Had disease progression prior to treatment
* Expected survival ≥ 3 months
* ECOG performance status of 0, 1, or 2
* With a negative pregnancy test for females of childbearing age
* Able to take effective contraceptive measures and ensure that there is no birth plan within half a year of the study
* Not positive for HIV, HBV, HCV, or TP
* ALT/AST ≤ 2.5 times the upper limit of normal
* ALP ≤ 2.5 times the upper limit of normal
* Serum creatinine ≤1.6 mg/dL
* Total bilirubin ≤ 1.5 mg/dL
* In the absence of granulocyte colony-stimulating factor support, proportion of lymphocytes \> 20%, absolute neutrophil count ≥ 1x10\^9/L, white blood cell count ≥ 3x10\^9/L, platelet count ≥ 100×10\^9/L, hemoglobin \> 8.0 g/dL, CD4+ cell count \> 200/μL
* With normal coagulation test and ECG
* Able to understand and willing to sign a written informed consent form
Exclusion Criteria:
* Pregnant or breastfeeding women
* Patients with brain metastases
* Had immunosuppressant therapy within 1 month or received other immunotherapy within 3 months
* Participated in other clinical study within 30 days
* With severe allergies or histories of severe allergy
* With splenectomy
* With primary or secondary immunodeficiency diseases or autoimmune diseases (including systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, autoimmune thyroid disease, multiple sclerosis, vasculitis, glomerulitis, psoriasis, uncontrolled asthma, etc.)
* Had oral, intramuscular, or intravenous corticosteroids within 1 month. However, inhaled corticosteroids are allowed to treat respiratory insufficiency (such as chronic obstructive pulmonary disease), as well as topical steroids
* With uncontrollable epilepsy, central nervous system disorder, or neurological disease with loss of cognitive ability
* With a history of chronic alcohol or drug abuse within 6 months
* With unstable systemic diseases (including active infection, liver cirrhosis, chronic renal failure, severe chronic pulmonary disease, unstable hypertension, unstable angina, congestive heart failure, myocardial infarction within 1 year, etc.)
* With a history of other malignant tumors in the past 5 years (excluding those who have been clinically cured, and squamous cell carcinoma or skin basal cell carcinoma)
* Those the researcher believed inappropriate to participate in this study
