In Call of Duty: Black Ops 6, in addition to Omnimovement, Smart Move is introduced, an innovation designed to improve accessibility and fluidity of the game. In Keyboard and Mouse or Controller Settings under Movement, you can adjust the following features:

Sprint Assist: You can choose to sprint manually or automatically, set a tactical sprint, adjust the delay before sprinting, and decide whether to enable assistance when sprinting sideways or backwards (due to Omnimovement).

Cover Assist: Customize the settings for automatic cover, and choose to go over no objects, low obstacles, or all objects that can cover.

Crouch Assist: This feature helps you crouch and slide when you need to pass through a valid opening (i.e. where you need to crouch).

Corner Cutting: Allows you to tilt your weapon (and camera) when approaching or going around a corner, without affecting your aim. This feature is on by default.

Regarding the behavior of Sprint Assist, you can choose to turn it off (default), on, or only the options related to tactical sprinting:

Off: Manually activate the sprint button.
On: Full-force movement inputs will automatically activate a sprint after a delay.
Tactical Sprint Assist: Forward movement inputs will activate a tactical sprint after a delay, and sideways and backwards movement can also be activated separately.
Sprint Assist Delay: The amount of time (in milliseconds) before inputting an action activates Sprint Assist, selectable from zero (default) to 1,000 milliseconds (1 second) in 50 millisecond increments.
Sideways and Backwards Sprint Assist: On by default, allows Sprint Assist to be activated when moving in the specified direction.

Regarding the behavior of Mantle Assist, you can turn it off (default), set it to Low Mantle Assist, or turn it on:

Off: Mantle is contextually activated by the Jump button (movement on traversable objects).
Low Mantle Assist: Mantle Assist activates when sprinting towards low obstacles.
On: Mantle Assist is automatically activated when sprinting, and works for all traversable obstacles.
Sideways and Backwards: Mantle Assist is also activated when sprinting towards low obstacles sideways or backwards, off by default, but can be set to on for either direction.
Tactical Sprint Only: Mantle Assist is only activated when tactically sprinting, default is off.
Mantle Unload: Activates Mantle Assist when reloading, default is on.

Regarding Crouch Assist, you can enable or disable:

Off: The default setting, allowing you to crouch or slide manually using the “Change Stance” button.
On: Crouch Assist is automatically activated when walking towards a valid opening.
Tactical Sprint Only: Crouch Assist is only activated when tactically sprinting to a valid opening, default is off.