Abstract: Tumor-associated macrophages (TAMs) are critical components of the tumor microenvironment (TME) and represent an important class of immune cells. Under the influence of various signaling factors, TAMs can be polarized into two major phenotypes: classic activation of macrophage (M1) and alternative activation of macrophage (M2). M1-polarized TAMs predominantly exert pro-inflammatory and antitumor effects, whereas M2-polarized TAMs are primarily associated with anti-inflammatory and tumor-promoting activities. Owing of their phenotypic plasticity, strategies aimed at reprogramming M2-type TAMs to adopt the M1 phenotype have emerged as promising and novel approaches in cancer therapy. Significant progress has been made through multifaceted investigations that include in vitro studies, use of animal models, and clinical research. This review summarizes the plasticity of TAMs, their functional roles in different types of cancers, and recently reported therapeutic strategies targeting TAM polarization.