Fig. 1: Different immunotherapy approaches.

They mainly include immune checkpoint inhibitors, adoptive immune cell therapy, tumor vaccine and cytokine-based therapy. Among the immune checkpoint inhibitors, PD-1/PD-L1 inhibitors block the interaction between PD-1 and PD-L1, preventing the inhibition of anti-tumor activity of cytotoxic T cells and thus eliminating tumor cells. Similarly, CTLA-4 inhibitors enable T cells to proliferate massively and attack tumor cells by binding CTLA-4 molecules. As shown in the figure, the currently approved drugs for NSCLC are nivolumab, pembrolizumab, cemiplimab targeting PD-1; atezolizumab, durvalumab targeting PD-L1 and ipilimumab, tremelimumab targeting CTLA-4. Adoptive immune cell therapy is exemplified by chimeric antigen receptor (CAR) T-cell therapy. Technicians isolate and purify T cells from the blood of a tumor patient. A viral vector containing a CAR that recognizes tumor cells and activates T cells is genetically engineered into the T cells, transforming T cells into CAR-T cells. The CAR-T cells are cultured in vitro to expand in large numbers, and then reinfused into the patient’s body, where they can specifically recognize tumor cells and efficiently kill them through immune effect. As for cancer vaccines, one of them involves removing cancer cells from a patient’s tumor, isolating cancer antigens and mixing these antigens with adjuvants that enhance the immune response, and injecting them back into the patient. The immune system can then recognize and attack cancer cells. Another type of cancer vaccine uses dendritic cells. Dendritic cells are removed from the blood and loaded with cancer antigens outside the body. The dendritic cells then take up the cancer antigens and post them on the cell surface. When injected back into the body, these antigen-rich dendritic cells trigger an immune response to the cancer. Finally, cytokine-based therapy suppresses tumors by directly administering exogenous cytokines that effectively activate immune cells in the body or counteract immune suppression.