CD4 and neoplasm: Intratumoral application of IL-12 was shown to enhance the activity of CAR T cells designed to target the tumor-associated antigen epidermal growth factor receptor variant III in an immunocompetent, orthotopic glioblastoma multiforme mouse model.2 In addition to improved CAR T cell activity, local IL-12 application led to lower Treg cell numbers, higher proinflammatory CD4+ T cells, and greater activation of myeloid cells in the remodeled TME, with only limited systemic effects.