CD274 and B-cell chronic lymphocytic leukemia: In NHLs B cell lymphomas, the highest level of PD-L1 expression has been observed in diffuse large B cell lymphoma (DLBCL), followed by small lymphocytic lymphoma (SLL), mantle cell lymphoma (MLC), while follicular lymphoma (FL) had the lowest PD-L1 expression level (15, 16).