Dual-Target GD2/B7-H3 CAR-NK Cells for Pediatric Relapsed or Refractory Neuroblastoma

Inclusion Criteria: * Age 12 months to 21 years at consent/assent. * Histologically confirmed neuroblastoma or ganglioneuroblastoma with relapsed, refractory, progressive, or persistent high-risk disease for which no curative standard option is available. * Measurable or evaluable disease according to revised International Neuroblastoma Response Criteria (rINRC), including MIBG-avid disease, CT/MRI-evaluable soft-tissue disease, and/or bone marrow disease. * Tumor material available for central assessment of GD2 and B7-H3 expression; at least one target must be positive. GD2 is treated as the core target and B7-H3 as the complementary target for correlative target-prioritization analyses. * Prior exposure to standard neuroblastoma therapy, including anti-GD2-based therapy, unless contraindicated, unavailable, or declined for a documented medical reason. * Lansky or Karnofsky performance score \>= 50. * Life expectancy \>= 8 weeks. * Recovery from clinically significant acute toxicities of prior therapy and protocol-defined washout from chemotherapy, biologics, radiation, and prior cell therapy. * Adequate organ function: hematologic, renal, hepatic, cardiac, and pulmonary function considered sufficient by protocoldefined laboratory and clinical thresholds. * Negative pregnancy test for patients of childbearing potential and agreement to use effective contraception during the protocol-defined period. * Written informed consent from parent/legal guardian and assent from the participant when appropriate. Exclusion Criteria: * Active uncontrolled infection, including bacteremia, uncontrolled viral infection, or invasive fungal disease. * Pregnancy or breastfeeding. * Active grade \>= 2 graft-versus-host disease, or systemic immunosuppression for treatment/prevention of graft-versushost disease within the protocol-defined washout period after prior allogeneic transplant. * Symptomatic or unstable central nervous system disease requiring urgent medical intervention. * Prior genetically modified cellular therapy within the protocol-defined washout window, or unresolved clinically significant toxicity from prior cell therapy. * Active autoimmune disease requiring systemic immunosuppressive therapy. * Clinically significant uncontrolled cardiovascular, pulmonary, hepatic, renal, or neurologic disorder that would increase study risk. * Known hypersensitivity to fludarabine, cyclophosphamide, study-product components, or supportive-care medications required by the protocol. * Known uncontrolled HIV infection or uncontrolled hepatitis B or C. * Any medical, psychosocial, or logistical condition that, in the investigator's judgment, would make study participation unsafe or would impair protocol adherence.