Among recurrent or metastatic NPC (RM-NPC) patients with poor prognosis who have progressed on second-line chemotherapy and beyond, a series of prospective phase II studies have examined the efficacy of anti-PD-1 immune checkpoint inhibitors (ICIs) alone and demonstrated an objective response rate (ORR) ranging from 20.5% to 34.1% (9–12). The gene discussed is PDCD1; the disease is nasopharyngeal carcinoma.