While immunotherapy has demonstrated encouraging efficacy in locally advanced nasopharyngeal carcinoma (LANPC), the optimal combination modalities and treatment duration remain undetermined. In the present study, we developed a clinical trial protocol to evaluate shortened period of immunotherapy could enhance the efficacy of LANPC. This open-label, randomized, single-blind, multicenter phase II trial (Tori-013) investigates the efficacy and safety of toripalimab (anti-PD-1 monoclonal antibody) combined with induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CCRT) in patients with stage III/IVa nasopharyngeal carcinoma (NPC). Eligible participants (estimated n=154) are randomized 1:1 to receive either IC (gemcitabine + cisplatin) plus CCRT (cisplatin + radiotherapy ≥ 70 Gy) with toripalimab (240 mg, Q3W) or placebo. Toripalimab/placebo is administered during IC and CCRT phases, followed by two additional cycles post-radiotherapy. The primary endpoint is 3-year progression-free survival (PFS), with secondary endpoints including overall survival (OS), objective response rate (ORR), Epstein-Barr virus (EBV) DNA dynamics, lymphocyte subset changes, and safety. Safety assessments focus on immune-related adverse events (irAEs) graded by CTCAE v5.0. Approved by the Ethics Committee of Sichuan Cancer Hospital (KY-2021-113) and registered (ChiCTR2200055494), this trial aims to establish a novel, streamlined immunochemoradiotherapy strategy for locally advanced NPC, potentially enhancing efficacy while maintaining tolerability.