Sintilimab, a highly selective monoclonal IgG4 antibody against PD-1, which works by blocking the association between PD-1 and its ligands, has been approved by the National Medical Products Administration (NMPA) of China to treat relapsed or refractory classical Hodgkin lymphoma in patients [19, 20]. The gene discussed is PDCD1; the disease is Hodgkins lymphoma.