The current achievements of immune checkpoint inhibitor therapy in the treatment of cancer and the newly discovered immune checkpoints in recent years

Immune checkpoint inhibitor therapy (ICIs) is a new type of cancer treatment method developed in the past 20 years and is a very eye-catching innovation in the development of clinical immunotherapy. With the emphasis on cancer treatment and our deepening understanding of the human immune system and malignant tumors, the mechanisms of various immune cell responses involved in cancer recognition and elimination have been gradually discovered and clarified one by one [2]. This therapy aims to enhance and activate the anti-tumor immune activity of cytotoxic T cells by blocking negative regulatory molecules on anti-tumor T cells or ligands on antigen-presenting cells and tumor cells through immune inhibitors. This therapy is of considerable importance in the current treatment and research of immuno-oncology. From the beginning, it was only used to treat a specific tumor to gradually treat a variety of different and common tumors. At the same time, it has also been used since the beginning. What started as a single specific inhibitor or two gradually developed into various dosage forms that can be combined. It has become one of the most clinically important methods for treating cancer.