Inclusion Criteria:

        Patients are eligible for screening for potential inclusion in the study:

          1. Voluntarily signed the ICF;

          2. Age ≥ 18 and ≤ 80 years with pathologically/histologically confirmed diagnosis of
             adenocarcinoma of the stomach or gastroesophageal junction, referred to collectively
             as STAD, or pancreatic adenocarcinoma (PAAD);

          3. Must have CLDN18.2-positive tumor expression as determined by the CLDN18.2 IHC assay;

          4. Age ≥ 18 and ≤ 80 years with pathologically/histologically confirmed diagnosis of
             STAD, or PAAD who have failed or been intolerant of prior lines of systemic therapy;

          5. Estimated life expectancy > 12 weeks;

          6. At least 1 measurable lesion per RECIST 1.1;

          7. ECOG performance status of 0 or 1;

          8. Sufficient venous access for leukapheresis collection and no other contraindications
             to leukapheresis;

          9. Patients should have reasonable CBC counts, renal and hepatic functions;

         10. Women of childbearing age must undergo a serum pregnancy test with negative results
             before screening and infusion and be willing to use effective and reliable method of
             contraception;

         11. Men must be willing to use effective and reliable method of contraception for at least
             6 months after T-cell infusion;

        Exclusion Criteria:

          1. Pregnant or lactating women;

          2. HIV, active hepatitis C virus (HCV), or active hepatitis B virus (HBV) infusion;

          3. Any uncontrolled active infection;

          4. AEs from previous treatment that have not recovered;

          5. Patients who have clinically significant thyroid dysfunction;

          6. Patients allergic to any drugs of the preconditioning regimen, tocilizumab, dimethyl
             sulfoxide (DMSO), or CT041 CAR-CLDN18.2 T-cell;

          7. Patients who have received prior cellular therapy such as (CAR T, TCR,
             tumor-infiltrating lymphocytes) or organ transplantation; Untreated central nervous
             system (CNS) metastatic disease, leptomeningeal disease, or cord compression;

          8. Patients with heavy tumor burden such as significant lung disease

          9. Unstable/active ulcer or digestive tract bleeding or recent digestive surgery that may
             have increased risk of bleeding;

         10. Patients who have a history of esophageal or gastric resection with increased risk of
             bleeding or perforation;

         11. Patients requiring anticoagulant therapy such as warfarin or heparin;

         12. Patients requiring long-term antiplatelet therapy;

         13. Use of prednisone or other equivalent within 14 days before leukapheresis or
             preconditioning;

         14. Anticancer treatment within approximately 2 weeks prior to leukapheresis or
             approximately 3 weeks before preconditioning;

         15. Major surgery less than 1 week prior to leukapheresis or 3 weeks prior to
             preconditioning;

         16. Patients have clinical significant cardiac conditions that researchers believe that
             participating in this clinical trial may endanger the health of the patients;

         17. Patients have clinical significant pulmonary conditions;

         18. Patients known to have active autoimmune diseases;

         19. Patients with second malignancies in addition to STAD or PAAD;

         20. Patients have significant neurologic disorders;

         21. Patients are unable or unwilling to comply with the requirements of clinical trial.