Tracking versus flicking
A flick is one committed movement that ends in a click. It is over in a fraction of a second and judged on a single moment. Tracking is judged continuously: what counts is the share of time your crosshair was on the target, not any one instant.
They use different control. A flick is largely pre-programmed before the hand starts moving. Tracking is a correction loop, your eyes feeding small adjustments to your hand many times a second while the target keeps changing where it is.
Which games reward it
Sustained tracking matters most where time to kill is long and weapons are automatic: hero shooters, arena shooters, battle royales at close range. If killing something takes a second of continuous fire, a second of continuous accuracy is the skill.
In tactical shooters like CS2 and Valorant, where a headshot ends the fight, tracking matters less than crosshair placement and the first accurate shot. It still appears whenever you hold an angle on a strafing opponent.
Smoothness, not speed
The common mistake is treating tracking as a series of tiny flicks: jerk onto the target, overshoot, jerk back. It feels active and it costs time on target. Good tracking looks slow and boring, the crosshair drifting along with the target rather than chasing it.
A sensitivity you can control matters more here than anywhere else. If you cannot hold a steady line, your cm/360 may be too fast for the joints you aim with.
How to train it
AimBetween has two tracking modes for two different problems. Tracking mode keeps a target moving continuously and scores the share of the round your crosshair spent on it, with no clicking at all. Strafe mode adds direction changes and asks for a click on the turn, which is the specific skill of reading a strafing player.
Start with a slower target and a longer round. The number to move is time on target, not reaction speed.