It can also be induced on T cells, NK cells, and many types of cancer cells.215–217 B7-H3 inhibits T cell immunity, especially Th1 immunity by acting directly on T cells218,219 or indirectly on DCs.220 However, a co-stimulatory receptor, triggering receptor expressed on myeloid cells (TREM)-like transcript 2 (TLT-2, TREML2) expressed on CD8+ T cells constitutively and on activated CD4+ T cells, has been identified as a receptor of B7-H3, and their ligation promotes T cell immunity221 (Fig. 2). Here, TREML2 is linked to cancer.