Macrophages are versatile immune cells that maintain homeostasis and defend against pathogens. They can be polarized into distinct functional states, primarily M1 (classically activated) and M2 (alternatively activated), based on environmental cues. M1 macrophages are activated by IFN-γ and LPS, exhibiting pro-inflammatory properties and promoting Th1 responses. M2 macrophages, further divided into M2a, M2b, and M2c, are alternatively activated and support Th2 responses, tissue repair, and anti-inflammatory functions. M2a is activated by IL-4 or IL-13, M2b by immune complexes and IL-1β or LPS, and M2c by IL-10, TGF-β, or glucocorticoids. M1 macrophages are effective at microbial killing and produce IL-12, while M2 macrophages clear debris and promote tissue repair. Tumor-associated macrophages (TAMs) often exhibit M2-like characteristics, contributing to tumor progression. Macrophage polarization is crucial in both infection and non-infectious diseases, influencing inflammation resolution and tissue repair. Understanding macrophage polarization has implications for therapeutic strategies in cancer and other diseases. The field is still evolving, with ongoing research to clarify the mechanisms and functional roles of different macrophage subsets.Macrophages are versatile immune cells that maintain homeostasis and defend against pathogens. They can be polarized into distinct functional states, primarily M1 (classically activated) and M2 (alternatively activated), based on environmental cues. M1 macrophages are activated by IFN-γ and LPS, exhibiting pro-inflammatory properties and promoting Th1 responses. M2 macrophages, further divided into M2a, M2b, and M2c, are alternatively activated and support Th2 responses, tissue repair, and anti-inflammatory functions. M2a is activated by IL-4 or IL-13, M2b by immune complexes and IL-1β or LPS, and M2c by IL-10, TGF-β, or glucocorticoids. M1 macrophages are effective at microbial killing and produce IL-12, while M2 macrophages clear debris and promote tissue repair. Tumor-associated macrophages (TAMs) often exhibit M2-like characteristics, contributing to tumor progression. Macrophage polarization is crucial in both infection and non-infectious diseases, influencing inflammation resolution and tissue repair. Understanding macrophage polarization has implications for therapeutic strategies in cancer and other diseases. The field is still evolving, with ongoing research to clarify the mechanisms and functional roles of different macrophage subsets.