• Age: 1-18 years old;

• ECOG PS score: 0-1 points;

• Pathologically confirmed newly diagnosed children or adolescents with intermediate to high-risk rhabdomyosarcoma;

• Patients evaluated by surgery as having a high degree of difficulty;

• Must have at least one measurable lesion defined by RECIST or WHO criteria;

• Expected survival time ≥ 6 months;

• Cardiac function:

∙ Echocardiography shows LVEF ≥ 50%;

‣ EKG indicates no evidence of myocardial ischemia;

‣ No history of arrhythmia requiring pharmacological intervention before enrollment;

• No history of severe immune-related adverse events (CTCAE V4.03 G3 or G4);

• For patients with known non-involvement of the bone marrow (BM):

∙ Absolute neutrophil count (ANC) ≥ 1.0 × 109/L;

‣ Platelet count ≥ 100.0 × 109/L;

‣ Hemoglobin ≥ 90 g/L;

⁃ Liver and kidney functions need to meet the following criteria:

• Total bilirubin (conjugated + unconjugated) ≤ 2.5 × upper limit of normal (ULN) corresponding to age, patients with confirmed Gilbert's syndrome may be enrolled based on the investigator's discretion;

∙ Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 × ULN;

∙ Estimated glomerular filtration rate ≥ 30 mL/min/1.73 m2 or serum creatinine (Cr) ≤ 1.5 × ULN;

⁃ Able to comply with outpatient treatment, laboratory monitoring, and necessary clinical visits during the study;

⁃ The parents/guardians of the child or adolescent participants have the ability to understand, consent to, and sign the informed consent form (ICF) and applicable child consent forms before initiating any protocol-related procedures; the participants have the ability to express their consent (if applicable) with the consent of their parents/guardians.