Malignant B cells are in frequent contact with PD-L1⁺ TAMs. (A) Representative high-power mIF image demonstrating PD-L1 expression on the surface of CD68⁺ TAMs in contact with a PAX5⁺ malignant B cells. (B) Cell-cell contact map of the mIF image shown in panel A (same scale). PD-L1⁺ TAMs, PD-L1⁻ TAMs (not present in the image), and other cells in contact with malignant cells and PD-L1⁺ TAMs and PD-L1⁻ TAMs not in contact with malignant cells are indicated. (C) Proportion of malignant B-cell contacts for individual cases (●) displayed according to the proportion of contacts with PD-L1⁺ TAMs vs PD-L1⁻ TAMs (n = 26). (D) Low-power, maximum field-of-view mIF image of TCRLBCL shown in panel A. (E) Cell phenotype map corresponding to the mIF image in panel D: PD-L1⁺ TAMs, PD-L1⁻ TAMs, and malignant cells are indicated. (F) TAM density for individual cases (●) displayed according to the density of PD-L1⁺ TAMs and PD-L1⁻ TAMs. (G) Intermediate-power mIF image of the region highlighted in panel D: PD-L1 expression on CD68⁺ TAMs and PAX5⁺ B cells. (H) Cell proximity map of the region highlighted in panel E, showing the spatial distribution of PD-L1⁺ TAMs and PD-L1⁻ TAMs relative to malignant B cells (<75 μm and ≥75 μm). (I) The ratio of PD-L1⁺ TAMs to total TAMs for individual cases (●) displayed according to whether the TAMs are located <75 or ≥75 μm from malignant B cells. For the box-and-whisker plots (C, F, I) the median (line), 25th and 75th percentiles (boxes), and extreme values (whiskers) are indicated. Statistical comparisons by 2-sided Mann-Whitney U test, Wilcoxon matched-pairs signed rank test, and the Kruskal-Wallis test with Dunn’s test for multiple comparisons.