This study focuses on treating nasopharyngeal carcinoma (NPC), a type of cancer in the upper part of the throat behind the nose, with a combination of a drug called nivolumab and chemotherapy. Nivolumab is an immunotherapy drug that helps the body's immune system fight cancer cells. The chemotherapy drugs used, gemcitabine and cisplatin, help stop cancer cells from growing and spreading. This study is testing if adding nivolumab to the treatment plan is safe and effective for patients aged 21 and under. The study includes three phases of treatment: induction, consolidation, and maintenance therapy, with each involving different combinations of the drugs and radiation therapy.

• The study lasts up to 5 years with regular follow-ups.
• Participants must be ≤ 21 years old and newly diagnosed with NPC.
• Potential risks include side effects from drugs and radiation therapy.

Participants will undergo various tests, including MRIs and CT scans, to monitor progress. Eligibility requires certain health criteria to be met, and some conditions may exclude participation. Always consult with healthcare providers before deciding to join a study.