PDCD1 and Hodgkins lymphoma: Data from a phase II clinical trial in relapsed or refractory Hodgkin lymphoma shows that, compared to monotherapy with camrelizumab, patients treated with Decitabine and camrelizumab (anti-PD-1 monoclonal antibody) combination therapy have an increased percentage of circulating peripheral central memory T cells, an overall remission rate (ORR) of up to 95%, and significantly prolong progression-free survival (PFS) [195].