Fig. 2
From: Combination regimens with PD-1/PD-L1 immune checkpoint inhibitors for gastrointestinal malignancies
Combination strategy in tumor immune circulation. As described in the cancer-immunity cycle, there are three main stages involving the presentation of tumor cell antigen by the APC cells, primary activation of T cells in the lymph node, and migration of cytotoxic T cells from the vessel to kill the tumor cells. Several other types of antitumor therapy, such as radiotherapy, chemotherapy, another immunotherapy, and targeted therapy, can participate in the cancer-immunity cycle by destroying the tumor matrix, increasing antigen exposure, removing the immunosuppressive factors, promoting the infiltration of T cells, etc.