Study to Evaluate the Safety, Tolerance, Pharmacokinetics and Preliminary Efficacy of IBI345

Inclusion Criteria: 1. Age ≥18 years and ≤75 years. 2. Histologically or cytologically confirmed CLDN18.2 positive patients with advanced gastric cancer or pancreatic cancer who failed standard therapy . 3. There are assessable lesions according to RECIST V1.1 (solid tumor efficacy evaluation criteria). 4. Expected survival time ≥12 weeks. 5. ECOG PS 0\~1. Exclusion Criteria: 1. Participating in another interventional clinical study, other than observational (non-interventional) clinical study or in the survival follow-up phase of the interventional study. 2. Received any antitumor drug within 2 weeks prior to apheresis or initial administration of the investigational drug. 3. Use of immunosuppressive drugs within 1 week prior to apheresis or 2 weeks prior to initial administration of the investigational drug. 4. Long-term systemic steroid or any other immunosuppressive drug therapy is required, not including inhaled steroid therapy. 5. Receive live attenuated vaccine within 4 weeks prior to initial administration of the study drug or plan to receive live attenuated vaccine during the study period. 6. Toxicity (excluding alopecia, fatigue, and hematological toxicity) that did not return to equal to or lower than Grade 1 of NCI CTCAE V5.0 from previous antitumor therapy prior to initial administration of the investigational drug.