The results of flow cytometry showed that the expression levels of CD4+ T cell PD-1, CD4+ T cell PD-L1, and CD8+ T cell PD-1 in peripheral blood of cHL and PTCL patients were higher than those of the healthy control group (Fig. 1A, Table 2). Here, CD4 is linked to mature T-cell and NK-cell non-Hodgkin lymphoma.