PDCD1 and cancer: Toripalimab, a recombinant, humanized programmed death receptor-1 (PD-1) monoclonal antibody that binds to PD-1 and prevents binding of PD-1 with programmed death ligands 1 (PD-L1) and 2 (PD-L2), is being developed for the treatment of various cancers in China (3).