CD274 and neoplasm: Immunohistochemistry (IHC) analysis revealed sparse CD8+ T cells but abundant CD163+ tumor-associated macrophages (TAMs) in AT-3, B16, and 4T1 tumors compared to MC38 tumors (Supplementary Fig. 1b), consistent with a positive correlation between CD8+ tumor-infiltrating lymphocytes (TILs) frequency and response to anti-PD-L1 therapy2, and validating AT-3, B16, and 4T1 tumors as models for poorly T cell-infiltrated tumors refractory to anti-PD-L1 therapy.