Dual-Targeting CAR-NK Cells Targeting Mesothelin (MSLN) and MUC1 in Advanced Pancreatic Ductal Adenocarcinoma

Inclusion Criteria: * Age 18 to 75 years at the time of consent. * Histologically or cytologically confirmed pancreatic ductal adenocarcinoma (PDAC). * Unresectable locally advanced or metastatic disease with progression after at least 1 prior standard systemic therapy regimen, or intolerance/ineligibility for standard therapy. * At least 1 measurable lesion per RECIST v1.1. * Tumor antigen expression by central IHC (archival or fresh biopsy): • Arm A eligibility: MSLN positive and/or MUC1 positive. • Arm B eligibility: CLDN18.2 positive and/or MUC1 positive. (Example threshold: IHC 2+ or 3+ staining in \>=50% of tumor cells, or H-score above protocol-defined cutoff.) * ECOG performance status 0-1. * Adequate organ function (example): ANC \>= 1.0 x 10\^9/L; platelets \>= 75 x 10\^9/L; hemoglobin \>= 8 g/dL; AST/ALT \<= 3x ULN (\<= 5x ULN with liver metastases); total bilirubin \<= 1.5x ULN; creatinine clearance \>= 50 mL/min. * Life expectancy \>= 12 weeks. * Negative pregnancy test for individuals of childbearing potential; agreement to use effective contraception during study participation and for a protocol-defined follow-up period. * Ability to understand and willingness to sign written informed consent. Exclusion Criteria: * Active or untreated CNS metastases or carcinomatous meningitis. * Clinically significant uncontrolled infection (including uncontrolled bacterial, fungal, or viral infection). * Known active hepatitis B or hepatitis C with detectable viral load; known uncontrolled HIV infection * Prior allogeneic hematopoietic stem cell transplant or solid organ transplant. * Prior gene-modified cellular therapy (e.g., CAR-T/CAR-NK) within 6 months or prior therapy targeting the same antigen(s)