ALCAM and neoplasm: For instance, macrophages with high ALCAM expression colocalized with depleted CD8+ T cells in the tumor microenvironment to promote T cell depletion, and the inhibition of HIF-1ɑ could reduce the expression of ALCAM in macrophages and deplete CD8+ T cells, thereby improving the effect of immunotherapy by enhancing the anti-tumor function of T cells [35].