CXCL9 and viral infectious disease: The expression of CXCR3 ligands, CXCL9 and CXCL10, is key IFN-induced environmental cues that regulate T cell positioning and function during acute and chronic viral infection, and recall responses (De Giovanni et al., 2020; Duckworth et al., 2021; Ozga et al., 2022; Sung et al., 2012).