PD-L1 signature was validated in primary DLBCL samples. (A) Scatter plots comparing CD274, STAT3, and IL-10 mRNA expression levels in GCB vs ABC subtypes of DLBCL. (B) Scatter plots comparing PD-L1 and pSTAT3 protein expression in GCB vs ABC DLBCL subtypes. (C) Scatter plots comparing pSTAT3 protein expression, as well as STAT3 and IL-10 mRNA expression, in PD-L1⁺ vs PD-L1⁻ DLBCL cases. (D) Scatter plots comparing PD-L1 protein expression and IL-10 mRNA expression levels in pSTAT3^lo/pSTAT3⁻ vs pSTAT3^hi/pSTAT3⁺ DLBCL cases. (E) Scatter plots comparing CXCL10 mRNA levels in GCB vs ABC, PD-L1⁻ vs PD-L1⁺, and pSTAT3⁻ vs pSTAT3⁺ DLBCL.