Compared with hematological tumors, T-cell transport and delivery in solid tumors are usually limited by the immunosuppressive microenvironment, which prevents T-cells from being transported and infiltrated to the tumor site by secreting a number of chemokines, such as CXCL1, CXCL12, and CXCL5, and the T cells express the lack of corresponding chemokine receptors, thus severely limiting the potency of CAR T-cells to kill tumor cells. The gene discussed is CXCL12; the disease is neoplasm.