Clinically, eradication of Tregs, downregulation of indolamine 2,3-dioxygenase (IDO; see Section 4.3), and improvement of the cytokine milieu are attempted with the use of lymphodepleting chemotherapy prior to CAR-modified IEC infusion, a strategy that may lead to improved treatment outcomes as indicated by studies in non-Hodgkin lymphoma [159]. This evidence concerns the gene IDO1 and non-Hodgkin lymphoma.