Higher pretreatment fractions of PD-L1⁺ HRS and PD-L1⁺ macrophages within the TME are associated with response. mIF imaging was performed to quantify PD-L1 expression, TAMs, and B cells. Cells were phenotyped as PD-L1⁻ CD163⁺ macrophages, PD-L1⁺ CD163⁺ macrophages, PD-L1⁻ HRS cells, PD-L1⁺ HRS cells, or CD79a⁺ B cells. Representative images (scale bar, 50 μm) with displayed phenotypes are shown for a patient with CR (A) and a patient with PR (B). The percentage of all TME cells expressing PD-L1 (C), the percentage of HRS cells expressing PD-L1 (D), the density of PD-L1⁺ CD163⁺ macrophages (E), the percentage of CD163⁺ cells expressing PD-L1 (F), and density of all CD163⁺ macrophages (G) were compared between patients with CR or PR/SD/PD. The combined density of PD-L1⁺ HRS cells and PD-L1⁺ CD163⁺ macrophages (H) as well as their frequency among all TME cells (I) is shown. Similarly, CD79⁺ B cells densities were compared (J). Statistics are generated using unpaired Student t tests.