The study will consist of 2 phases, a Phase I or dose escalation phase and a Phase II or expansion phase. Paediatric or young adult patients with relapsed High Risk and/or relapsed/refractory Neuroblastoma will be enrolled in the study. Eligible patients will undergo leukapheresis in order to harvest T cells, which will be manufactured to obtain the autologous CAR T product GD2-CART01, a GD2-targeting CAR T product. Briefly, the patients will be treated with a lymphodepleting regimen containing conventional chemotherapic agents and subsequently will receive a single infusion of GD2-CART01. Moreover, the product contains a suicide gene safety switch (namely inducible Caspase 9): in case of relevant toxicities, the patient will receive the dimerizing agent in order to activate the apoptotic pathway in the infused T cells.