PDCD1LG2 and leukemia: Investigating PD-L1 and PD-L2 levels expressed by myeloid cells revealed that MERTK drives PD-L1 and PD-L2 expression on CD11b+ monocytes/macrophages and PD-1 expression on T cells in leukemia-bearing mice, contributing to an immunosuppressed milieu, supporting tumor growth [71].