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.