This multicenter, double-blind, randomized trial conducted in nasopharyngeal cancer (NPC)–endemic regions assesses whether toripalimab in combination with gemcitabine-cisplatin as first-line treatment for recurrent or metastatic NPC, compared with gemcitabine-cisplatin alone, will significantly improve progression-free survival and overall survival among chemotherapy-naive patients with recurrent or metastatic NPC.