Dying Light 2 Stay Human has no built-in head tracking. The free Dying Light 2 head tracking mod by itsloopyo adds it: it reads opentrack data, which LookPilot sends with the opentrack protocol, and lets you look around while your mouse or controller keeps aiming.
Install the Mod
Download the installer ZIP from the mod's Releases page
Right-click the ZIP, open Properties, tick Unblock and click OK, so Windows does not block the files inside
Extract it anywhere and double-click install.cmd
The mod needs Dying Light 2 v1.16 or later.
In-Game
Keep LookPilot running with the opentrack protocol
Launch Dying Light 2. Your head now moves the view, so you can look around while you run
Tips
If your shots land off the crosshair, turn off the movement axes (X, Y and Z) in LookPilot's tracking settings and keep only the rotation axes