CD4 and neoplasm: The TLR7/8 agonist imiquimod activates NK cells to kill tumor cells, leading to the release of tumor antigens and the induction of tumor-specific CD4+ T cells; at the same time, imiquimod induces the expression of CXCR3, a homologous chemokine receptor on peripheral lymphocytes, which triggers the infiltration and accumulation of CD4+ T cells within the tumor and is essential for tumor rejection [77].