A team of researchers at Stanford University has found a way to reinvigorate exhausted engineered CAR-T cells by giving them a time-out period to recover. In their paper published in the journal Science, the group describes giving the cells a time-out period, and how well it worked in giving them a new lease on life. Maksim Mamonkin and Malcolm Brenner with Texas Children’s Hospital have published a Perspective piece in the same issue outlining exhaustion in engineered CAR-T cells and the work done by the team in this new effort.