CD163 is a type I membrane protein primarily expressed on the surface of monocytes and macrophages and belongs to the scavenger receptor cysteine-rich (SRCR) superfamily. It plays a crucial role in regulating immune responses and clearing heme proteins. CD163 binds to haptoglobin-hemoglobin complexes, facilitating iron recycling and protecting tissues from oxidative damage. As a marker of M2-type macrophages, CD163 is associated with anti-inflammatory functions by inhibiting the production of pro-inflammatory cytokines. In pathological conditions, the expression levels of CD163 are linked to various diseases, including inflammatory disorders, cancer, and viral infections. Soluble CD163 (sCD163) is often used as a biomarker for disease monitoring and assessment.