CCL19 and non-small cell lung carcinoma: Using single-cell transcriptomic analysis, Onder et al. identified two main clusters of CCL19-expressing CAFs in human non-small cell lung cancer (NSCLC), resembling the transcriptional profiles of perivascular reticular cells (PRCs) and T-cell zone reticular cells (TRCs), previously characterized in lymphoid organs.1 These fibroblastic reticular cells (FRCs) are a specialized subset of stromal cells within immune-regulating structures.