GSL Synthetase Inhibitor Plus GM-CSF and/ or Immune Checkpoint Inhibitor in Previously Treated High-Risk Neuroblastoma.

Inclusion Criteria: 1. Neuroblastoma must be documented at the point of diagnosis, which is defined as one of the following: histopathology of a biopsy of a solid tumour; bone marrow aspirate or biopsy suggestive of neuroblastoma with elevated blood or urine catecholamine metabolite levels. 2. The participant is at least 6years old at time of enrollment. 3. At least one measurable lesion at baseline according to RECIST version 1.1. 4. Have adequate organ function as assessed by the laboratory required by protocol, which should be confirmed within 2 weeks prior to the first dose of study drugs. 5. Previous treatment must be completed for more than 4 weeks prior to the enrollment of this study, and subjects have recovered to \<= grade 1 toxicity. 6. Eastern Cooperative Oncology Group (ECOG) performance status score≤2 and Estimated life expectancy of more than 3 months. 7. Patient(and/ or their parent/ legal guardian) is willing to participate and able to provide signed informed consent. Exclusion Criteria: 1. Any systemic anti-cancer therapy, including chemotherapy or immunotherapy, within 3 weeks before 1st dose of GM-CSF 2. Existing major organ dysfunction \> Grade 2, with the exception of hearing loss, hematological status, kidney and liver function 3. Active life-threatening infection 4. History of allergy or intolerance to study drug components. 5. The participant is CYP2D6 ultra-rapid metabolizer. 6. The participant is known to be allergy to Eliglustat. 7. The participant use drugs that will strongly inhibit CYP2D6 or CYP3A activity.