PDCD1 and nasopharyngeal carcinoma: A phase I trial investigating camrelizumab (an anti-PD1 Ab) monotherapy in patients with metastatic NPC. Promising response with 59% 1-year overall survival (OS) was observed. A combination of gemcitabine, cisplatin and camrelizumab resulted in the best clinical outcome for patients with metastatic NPC although unacceptable high rate of grade >3 adverse events was observed.