Dual-Target HER2/CEA CAR-NK Cells in Advanced Biliary Tract Cancer

Inclusion Criteria: * Histologically or cytologically confirmed unresectable, recurrent, or metastatic intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, or gallbladder carcinoma. * Disease progression after at least 1 prior gemcitabine/platinum-containing regimen in the advanced setting; prior durvalumab and prior HER2-targeted therapy are allowed. * Central biomarker confirmation of HER2 positivity (IHC 3+ or IHC 2+/ISH+ or ERBB2 amplification) and CEACAM5/CEA positivity (membranous expression in \>=20% of viable tumor cells by IHC). * At least 1 measurable lesion according to RECIST 1.1. * ECOG performance status 0-1. * Adequate marrow, renal, hepatic, and cardiac function as defined by the protocol. * Resolved biliary obstruction or stable internal/external drainage for \>=7 days before lymphodepletion, with no active cholangitis. * Life expectancy \>=12 weeks. * Willingness to provide archival or fresh tumor tissue and serial blood samples for central biomarker testing and correlative studies. * Agreement to use protocol-specified contraception Exclusion Criteria: * Prior HER2-directed or CEA-directed gene-modified cell therapy. * Untreated or unstable CNS metastases or leptomeningeal disease. * Active uncontrolled infection, including uncontrolled cholangitis, sepsis, or clinically significant uncontrolled hepatitis or HIV infection. * Ongoing systemic immunosuppression greater than 10 mg/day prednisone equivalent within 7 days before lymphodepletion. * Clinically significant interstitial lung disease, uncontrolled heart failure, unstable arrhythmia, or recent myocardial infarction. * Child-Pugh B or C liver disease, hepatic encephalopathy, or clinically significant refractory ascites. * Prior allogeneic solid organ transplant or allogeneic stemcell transplant. * Active autoimmune disease requiring systemic therapy within the previous 2 years. * Pregnancy or breastfeeding. * Any condition that, in the investigator's judgment, would make lymphodepletion or EB-HC01 infusion unsafe or would interfere with protocol compliance.