,3 Features of the inflammatory microenvironment that have been reported to contribute to tumor progression and therapeutic resistance are hypovascularity, a dense fibrotic stroma with cancer-associated fibroblasts (CAFs),3,4 infiltration with myeloid-derived suppressor cells (MDSCs)5 and tumor-associated macrophages,6,7 ineffective cytolytic CD8+ T cells due to exhaustion,8,9 and increased numbers of CD4+ regulatory T (Treg) cells.10 The gene discussed is CD4; the disease is neoplasm.