MERTK and lung cancer: In vitro studies using lung cancer cell lines have demonstrated that sitravatinib suppresses the expression of markers associated with immunosuppressive phenotype macrophages via MERTK inhibition, preventing polarization into M2-type macrophages.13 In addition, in vivo studies using immune-competent mice have shown that sitravatinib leads to a reduction in intratumoral M2 macrophages and monocytic MDSCs, an increase in CD8+ T cells and a higher expression of pro-inflammatory genes, including PD-L1.13