PDCD1 and cancer: Besides the anti-PD-1 mAbs discussed here, a number of other anti-PD-1 mAbs have been approved by China or the European Union for treatment of different cancers, such as sintilimab, camrelizumab, toripalimab, tislelizumab, zimberelimab, prolgolimab, or dostarlimab; all of which have shown promising therapeutic effects for various cancer related indications (216).