Fig. 1From: Hurdles to breakthrough in CAR T cell therapy of solid tumorsTumor immunosuppressive microenvironment. The anticancer function of Infiltrated-CAR T cells is impeded by regulatory cells, immune checkpoint molecules (e.g., PD1 and CTLA-4), and immune inhibitory soluble mediators produced by tumor cells or tumor-associated cells. In addition, the metabolic profile of tumor tissue, especially hypoxia, impacts CAR T cell effector activity in TMEBack to article page