A large immune cell that engulfs pathogens, cleans up dead cells, and signals other immune cells about what it found.Macrophages are phagocytic cells of the innate immune system derived from monocytes. They exist on a polarization spectrum: M1 (classically activated, pro-inflammatory, antimicrobial) and M2 (alternatively activated, anti-inflammatory, tissue repair). Macrophage polarization is a key therapeutic target—several peptides modulate this balance. VIP and cortistatin promote M2 polarization; antimicrobial peptides like LL-37 and defensins activate M1 responses. Tumor-associated macrophages (TAMs) in the M2 phenotype promote cancer progression.