CD4 and breast cancer: For example, radiotherapy application in a murine breast cancer model increases the expression of CXCL16, a key element facilitating the recruitment of CXCR6+CD8+ effector T cells to the tumor microenvironment.433 In murine melanoma models, radiotherapy induces the release of both type I and type II interferons, leading to heightened levels of CXCL9 or CXCL10, thereby promoting the infiltration of effector T cells expressing CXCR3.434 Chemotherapy induces the secretion of chemokines like CCL5, CXCL9, and CXCL10 in the tumor microenvironment, attracting CD4+ and CD8+ T cells to the tumor site.