Target-Selected CAR-NK Cells (CD30, CD5, or Mesothelin) for Relapsed/Refractory B2 Thymoma or Thymic Carcinoma

Inclusion Criteria: * Age 18 to 75 years at the time of consent. * Histologically confirmed B2 thymoma or thymic carcinoma that is unresectable, metastatic, or recurrent. * Relapsed or refractory after at least 1 prior systemic therapy (including a platinum-based regimen for thymic carcinoma when appropriate) or no standard curative option available. * Tumor antigen positivity for at least one of the following by central laboratory assessment: CD30, CD5, or mesothelin. Cohort assignment is based on the dominant target (pre-specified algorithm) and feasibility of manufacturing/availability. * Measurable disease per RECIST v1.1 (or evaluable disease if measurable disease is not feasible; to be specified). * ECOG performance status 0-1 (0-2 may be permitted in expansion at investigator discretion). * Adequate organ function: ANC ≥ 1.0 x 10\^9/L, platelets ≥ 75 x 10\^9/L, hemoglobin ≥ 8 g/dL (transfusions allowed), AST/ALT ≤ 3 x ULN (≤ 5 x ULN with liver involvement), total bilirubin ≤ 1.5 x ULN (except Gilbert's), creatinine clearance ≥ 50 mL/min. * Negative pregnancy test for participants of childbearing potential; agreement to use effective contraception. * Ability to understand and sign informed consent. Exclusion Criteria: * Active central nervous system involvement by malignancy requiring immediate therapy. * Prior gene-modified cellular therapy (e.g., CAR-T, CAR-NK) within 90 days or unresolved ≥Grade 2 toxicity from prior cellular therapy. * Uncontrolled infection, including active tuberculosis, or uncontrolled hepatitis B or C infection; known uncontrolled HIV infection. * Clinically significant autoimmune disease requiring systemic immunosuppression (e.g., \>10 mg/day prednisone equivalent) within 14 days of conditioning, except for stable endocrine replacement. * Prior allogeneic hematopoietic stem cell transplant with active graft-versus-host disease or ongoing immunosuppression. * Significant cardiovascular disease (e.g., NYHA class III/IV heart failure, recent myocardial infarction), uncontrolled arrhythmia, or QTc prolongation felt to increase risk. * Pregnancy or breastfeeding. * Concurrent participation in another interventional trial with an investigational anticancer agent within 21 days (washout required). * Any condition that, in the investigator's judgment, would interfere with safe participation or interpretation of results.