AIM2 (Absent In Melanoma 2) belongs to the ALR family, possessing an HIN-200 domain for DNA binding and a PYD domain for interaction with the inflammasome adapter protein ASC. Predominantly localized in the cytoplasm, it detects pathogenic or stressed host double-stranded DNA, triggering AIM2 inflammasome assembly, activating caspase-1, and promoting secretion of pro-inflammatory cytokines such as IL-1β and IL-18, crucial for innate immunity and inflammatory responses. AIM2 expression exhibits tissue specificity in immune cells like macrophages and dendritic cells, pivotal in defense against bacteria, viruses, and tumors. Mutations or dysregulated expression of AIM2 correlate with autoimmune diseases, cancers, and infectious diseases. Research on AIM2 and its pathway provides profound insights into immune response mechanisms, offering potential therapeutic targets for diseases associated with dysregulated inflammasome activity.