At present, tumor therapy has entered the era of immunotherapy. However, in recent years, it has been found that the application of immune checkpoint inhibitors after chest radiotherapy can not only play a synergistic anti-tumor effect, but also cause radiation recall pneumonitis (RRP). RRP is a rare immune-related adverse reaction, which even leads to death in severe cases. It is of great significance to study the mechanisms and influencing factors of RRP caused by immune checkpoint inhibitors for strengthening the cognitive management of RRP and reducing the risk of RRP.