Tumor-infiltrating macrophages express immune-checkpoint molecules. (A) Box-and-whisker plots show PD-L1, IDO1 and PD-L2 mRNA levels, as revealed by nCounter. *P < .05, **P < .01 (Wilcoxon rank-sum test). (B) IF was performed using antibodies against CD3 (green, T cells), CD163 (pink, macrophages), PD-L1 (orange), and IDO1 (cyan). Representative images for cases with (right) or without (left) macrophage signatures are shown. Immunofluorescence; original magnification ×20. (C) Box-and-whisker plots represent average signal intensities of PD-L1 (top) or IDO1 (bottom) per cell among indicated cell types. Data were obtained from 3 independent macrophage signature–rich cases. Dots represent outliers. **P < .01 (Wilcoxon rank-sum test). (D) Heat map for hierarchical clustering of 68 PTCL-NOS cases based on expression levels of genes related to macrophage and tumor-associated inflammation. (E) Summary of 68 PTCL-NOS cases stratified based on microenvironmental immune cell signatures. Predictive prognostic values and proposed therapy are shown.