Evaluate the Safety and Efficacy of BGT007H Cell Therapy in Patients With Relapsed/Refractory Pancreatic Cancer

"Intervention roughly goes through 3 phases (the day of cell infusion is defined as day 0, d0):~1. Apheresis and baseline period: Eligible subjects are enrolled for leukapheresis to prepare BGT007H cell injection solution, and baseline assessment is performed from after apheresis to before preconditioning.~2. Preconditioning (d-5\~d-3): Patients begin preconditioning (FC regimen) 5 days before BGT007H cell administration. A 2-day rest and observation period is conducted after preconditioning.~ The FC regimen is as follows:~ * Fludarabine: 25\~30mg/m2/d, intravenous infusion, once a day, for 3 consecutive days;~ * Cyclophosphamide: 250\~350mg/m2/d, intravenous infusion, once a day, for 3 consecutive days.~3. Cell infusion (d0) and DLT observation period (d0\~d28)."