Slide cancelling was originally made popular with Black Ops 4. It allows you to chain tactical sprints together to move much faster than sprinting normally.
Simply push LS forward to run, then hold the crouch button to slide. As soon as you stop running and let go of the crouch button, your character will quickly return to a standing position giving you the ability to move around much faster.
“Auto Sprint” or “Auto Tactical Sprint” must be enabled In-Game for the Slide Cancel Mod to work.