XCL1 (X-C motif chemokine ligand 1) is a specialized chemokine that plays critical roles in immune cell recruitment and antitumor immunity. XCL1 functions as a chemoattractant specifically for lymphocytes, particularly natural killer (NK) cells and CD8+ T cells, but not for monocytes or neutrophils 1. The primary mechanism involves XCL1 binding to its receptor XCR1 on conventional type 1 dendritic cells (cDC1), facilitating their recruitment and activation 123. This XCL1-XCR1 axis is essential for establishing tissue-resident memory T cells (TRM) and supporting CD8+ T cell positioning during viral infections 4. In cancer contexts, XCL1 produced by NK cells and CD8+ T cells promotes cDC1 accumulation within tumors, enhancing antitumor immune responses and correlating with improved patient survival 12. XCL1 expression is associated with cytotoxic immune activities and granzyme B production 2. However, tumor cells may exploit XCL1 expression as an immune evasion mechanism, and XCL1 levels can influence chemotherapy sensitivity 5. Therapeutically, XCL1 represents a potential biomarker for immunotherapy response and a target for enhancing cancer treatment efficacy 36.