This is an overview of new IK Rig & IK Retargeting features that have been added to Unreal Engine 5.4. These include Auto Retargeting, Post Retarget Phase, QOL, and more. IK Rig & IK Retargeting is Unreal Engine’s retargeting system, a powerful toolset to let you craft robust retargeting setups for any types of characters with different skeletal hierarchies.
https://dev.epicgames.com/community/learning/talks-and-demos/vwG7/unreal-engine-ik-retargeting-5-4-features-at-a-glance