Working canines help search, guide, and attack enemies. Part of their training is learning to bite in an effort to not have to use a weapon against the enemy. Army scientists are now coming up with a bite sleeve trainers can wear when trying to train the dogs on how to bite, without getting the trainer hurt, while still creating a more realistic scenario.

Source: https://www.eurekalert.org/pub_releases/2020-07/uarl-asd072920.php