Abstract: Macrophages are the most important immune cells in tumor microenvironments. Macrophages of different origins and phenotypes play a variety of roles in tumor development. The PD-1/PD-L1 axis can be immunomodulated in a variety of ways to enable the tumor cells in evading the host immune system. TAMs regulate the (high) expression of PD-L1 via the activity of chemokines, autophagy, hypoxia-inducible factors, etc. However, the role and clinical significance of PD-L1⁺ macrophages in tumor progression remain controversial and, ultimately, unclear. The immunohistochemical staining techniques and scoring standards used are not uniform. This article summarizes the current status and progress of PD-L1⁺ macrophage research over the years.