Aging involves a decline in physiological functions and increased disease susceptibility, with the immune system playing a pivotal role. Recent research reveals that nonimmune structural cells, such as fibroblasts, epithelial cells, and neurons, develop immune-like properties crucial for stress response and tissue integrity. However, with aging, these organized, nonimmune cells in multicellular organisms gradually lose their identity and organization. They may exhibit unicellular properties, acquire macrophage-like characteristics, or enter a state of senescence, contributing to chronic inflammation.