Blocking the interaction of PD-1 and B7-H1 could reduce the conversion of Treg induced by malignant B cells in some cases of patients with B-cell NHL, which indicated that the Treg conversion of CD4+CD25− T cells might be mediated through the PD-1/B7-H1 pathway. Here, CD274 is linked to B-cell non-Hodgkin lymphoma.