(A and B) Representative multiplexed IHC images of human primary cutaneous melanoma samples. CD155 (green) was distributed broadly within the carcinoma element of human melanoma, identified by HMB45 positivity (orange). Tumor-infiltrating myeloid cells were revealed by CD14 (red) or CD11c (yellow) positivity. The dotted line circumscribes HMB45⁺ tumor cells in a representative human melanoma TMA core. The merged image shows high colocalization of CD155 and HMB45. Scale bars: 200 μm (A) and 50 μm (B). (C) Colocalization of CD155 in tumor-infiltrating myeloid cells in human melanoma. CD11c (yellow) and CD14 (red) discriminated different populations of tumor-infiltrating cells, including CD11c⁺CD14^– DCs (yellow arrows), CD11c⁺CD14⁺ myeloid cells (white arrows), and CD11c^–CD14⁺ monocytes/macrophages (red arrows). CD155 staining (green) was colocalized within each of these myeloid populations, as indicated in the merged panel. Scale bar: 50 μm. (A–C) Nuclei were stained with DAPI (blue) in each panel. (D and E) WT mice were injected s.c. with 1 × 10⁵ B16F10 cells (n = 5/group), and tumor samples were digested and analyzed on day 12. Tumor cells were gated by FSC^hiSSC^hiZombie-yellow^–CD45.2^– expression. (D) CD155 and PD-L1 expression on ex vivo B16F10 tumor cells is shown. (E) CD11b⁺CD11c⁺ and CD11b⁺CD11c^– tumor-infiltrating myeloid cell populations were gated by FSC^loSSC^loZombie-yellow^–CD45.2⁺ expression. CD155 and PD-L1 expression on these cells is shown. See also Supplemental Figures 1 and 2.