Although there is no information regarding ICOS or ICOS-L in ALL, the relevance of ICOS in ALL immune escape is supported by studies showing that ICOS is part of the intracellular region of the signaling domain complexes that activate and induce cytotoxicity against target cells during chimeric antigen receptor (CAR) T cell immunotherapy (127). The gene discussed is ICOS; the disease is acute lymphoblastic leukemia.