Immune checkpoint blockade (ICB) therapy targets checkpoint proteins to restore normal function to the immune system so that it can attack cancer cells. It is used successfully to treat a variety of cancers; however, many patients suffer from the development of immune-related adverse events (irAEs), which may affect any organ system and can be severe enough to cause the cessation of therapy. There is therefore great interest in understanding the mechanism of irAE development. Our work contributes to the understanding of the role of Treg plasticity and Treg-Th17 balance in the context of ICB treatment and irAE development that will guide future research in the field.