PDCD1 and cancer: In a large pan-cancer analysis, TGF-β signaling from cancer-associated fibroblasts (CAFs) positively correlated with a dysregulated extracellular matrix (ECM) transcriptional signature that was linked to immunosuppression and was a better predictor of failure to immune checkpoint blockade (ICB) targeting programmed death 1 (PD1) compared with other known biomarkers such as PD-L1 or TMB 6.