CXCL13 and neoplasm: Another study reported that the level of IL-21, IL-10, and CXCL13 are upregulated in PD-1+ CXCR5+ CD4 T cells in the GCs, which promotes CD8+ T cells to produce IFN-γ, induces the proliferation of B cells, and potentiates B cells to produce IgM and IgG, forming an anti-tumor immunity microenvironment [15].