CpG-ODN intra-tumoral injection activates DC, resulting in enhanced antigen presentation and subsequent tumour-antigen presentation to CD8+ T cells in tumour-draining lymph nodes. In addition, activated DCs secrete cytokines, recruit tumour-specific CD8+ T cells to the tumour site and directly kill tumour cells. By combining different therapeutic approaches including immunotherapy, chemotherapy, radiation therapy, photodynamic therapy and so on, the tumour microenvironment can be modulated to improve the anti-tumour responses.