CD200R1 and neoplasm: The activation of such chimeric receptor signaling was dependent on CD155 expression on tumor cells, contributed to rescue of hypofunctional T cells in the TME, and mediated robust antitumor cytotoxicity in murine xenograft models when combined with tumor-reactive TCR.38 CD200 is expressed on various types of tumor cells and binds CD200R on T cells to inhibit T cell activation.