This phase 3, multi-center, randomized controlled trial plans to enroll 532 patients with newly-diagnosed, pathologically-proven, untreated locoregionally advanced nasopharyngeal carcinoma (LANPC) at high-risk of distant metastasis (T4N1 and T1-4N2-3, according to American Joint Committee on Cancer [AJCC]/Union for International Cancer Control [UICC] 8th edition clinical staging system). Patients will receive 3 cycles of induction chemotherapy (IC; gemcitabine-cisplatin regimen) followed by 1) experimental arm (de-intensification group): intensity-modulated radiotherapy (IMRT) alone or 2) control arm (standard group): 2 cycles of concurrent cisplatin plus IMRT (CCRT). For both of the two arms, toripalimab will be adopted on day 1 of the first cycle IC and continue every 3 weeks for 6 cycles till the end of IMRT, with the first and last 3 cycles of toripalimab administrated along with IC and CCRT/IMRT, respectively. After three weeks of the completion of IMRT, adjuvant toripalimab will be used every 3 weeks for 11 cycles, and therefore the entire treatment process is expected to last for one year.