PDCD1 and nasopharyngeal carcinoma: Toripalimab is a PD-1 targeting humanized IgG4 monoclonal Ab that has been recently approved in combination with cisplatin and gemcitabine by US Food and Drug Administration (FDA) for the first-line treatment of adults with metastatic or recurrent locally advanced nasopharyngeal carcinoma (NPC), and as monotherapy for the treatment of adults with recurrent, unresectable or metastatic NPC with disease progression on or after platinum-containing chemotherapy.