MARCO refers to macrophage receptors with collagen structures, which are mainly found in M2 macrophages.La Fleur et al. showed that M2 macrophages in TAMs could be reverse polarized to M1 by targeting MARCO, thereby restoring the activity of CD8+T and NK cells, down-regulating Treg cells, and enhancing the anti-tumor capacity of immune system (La Fleur et al., 2021). The gene discussed is CD8A; the disease is neoplasm.