Chemotherapy modulates PD-L1 expression and its combination with immune checkpoint blockade requires precision

In recent years, cancer immunotherapy, particularly immune checkpoint blockade (ICB), has revolutionized the standard of care for some patients with advanced disease. However, ICB alone is often ineffective in the majority of cancer patients. Chemotherapy, a standard treatment aims at directly targeting rapidly growing tumor cells, also induces the release of antigens that may enhance anti-tumor immunity. Consequently, numerous clinical trials are investigating the synergistic effects of combining ICB with chemotherapy, and they are showing great promise. Additionally, chemotherapy can impact the expression of immune checkpoint molecules like PD-L1(programmed death-ligand 1), potentially influencing the efficacy of ICB. Moreover, chemotherapy has the potential to eliminate immune cells, underscoring the importance of selecting the appropriate chemotherapy agent and dose to optimize the combinational effect. This review systematically evaluates the influence of various chemotherapy agents on the PD-1/PD-L1(programmed cell death-1) immune checkpoint and summarizes the combined impact of chemotherapy and ICB across different cancer types. While the benefits of combination therapy are significant, the selection of chemotherapeutic agents should be tailored to individual patients. Personalized combination therapy involving ICB and chemotherapy has the potential to greatly enhance outcomes for cancer patients.