The researchers discovered that the T cell receptors are activated by a hidden spring-like movement that has not been observed before. The discovery may explain why immunotherapy works for some cancers. It could help improve its effectiveness in other types of tumors. T cells have receptors that allow them to attack cancer cells in immunotherapy. The hidden mechanism of receptor activation is a new breakthrough in understanding their functioning. Immunotherapy uses engineered T cells to destroy tumors, as shown by studies of CAR-T therapies. This finding could increase the success of treatment for more patients.