CD163 is a 130 kDa type I transmembrane glycoprotein and a member of the scavenger receptor cysteine-rich (SRCR) superfamily. It is exclusively expressed on monocytes and macrophages and is involved in the clearance and endocytosis of hemoglobin-haptoglobin complexes, which helps protect tissues from oxidative damage caused by free hemoglobin. The protein consists of nine SRCR domains, a single transmembrane segment, and a short cytoplasmic tail. CD163 is upregulated in macrophages during the switch to alternative activated phenotypes in inflammation and is considered a marker for anti-inflammatory macrophages. Elevated levels of soluble CD163, which result from the shedding of the membrane-bound form, have been observed in various acute and chronic inflammatory disorders, making it a potential biomarker for inflammation. Additionally, CD163 is being explored as a therapeutic target for delivering drugs to macrophages in inflammatory conditions.