XCL2 (X-C motif chemokine ligand 2) is a chemokine that functions primarily in immune cell recruitment and activation, particularly targeting lymphocytes rather than monocytes or neutrophils 1. The protein exhibits a unique metamorphic structure, exchanging between monomeric and dimeric forms under physiological conditions, with the monomeric form responsible for G protein-coupled receptor activation and the dimeric form important for glycosaminoglycan binding 1. XCL2 plays a critical role in tumor immunity by facilitating recruitment of conventional type 1 dendritic cells (cDC1) into the tumor microenvironment, where it correlates with NK cell gene signatures and improved patient survival 2. The chemokine supports tissue-resident memory T cell formation and positioning, with enforced expression promoting intratumoral cDC1 accumulation and enhanced T cell persistence, leading to improved tumor control 3. XCL2 expression is generally downregulated in tumor tissues and correlates with cancer prognosis, DNA methylation status, and immune cell infiltration patterns 4. Additionally, XCL2 has been implicated in various disease contexts, including serving as a potential diagnostic marker in Parkinson's disease progression through its specific expression in NK cell subclusters 5, and showing associations with bronchiectasis risk through DNA methylation-mediated mechanisms 6.