CD274 and B-cell non-Hodgkin lymphoma: Considering that a chemotherapy regimen for B‐cell NHL treatment is usually administrated every 3 weeks and plasma concentrations of these chemotherapeutic drugs become very low several days after drug infusion, we used sub‐toxic (sub‐therapeutic) concentrations (IC10) of these drugs in testing their effect on the expression of PD‐L1 in stromal cells.