PDCD1 and hepatocellular carcinoma: In the RNA-seq data of the TCGA, a higher CAF-FAP score is positively correlated with the increased CD8_PDCD1 score across 27 cancer types (P < 0.05; Fig. 7d; Supplementary Fig. S8b and Table S7), aligning with the physical juxtaposition of CAF-FAP and CD8_PDCD1 in HCC tumor stroma (Fig. 6f, g) and indicating a universal distribution of inflammatory hubs across multiple cancer types.