K'Sante vs Jax

Stack Ntofo Strikes (Q) on minions: after 2 hits, the next cast becomes a shockwave that stuns and pulls, so save it for the champion.

Charge Path Maker (W) when they throw CC at you: while charging, you're Unstoppable and take less damage, then your dash knocks back and stuns.

Cast Footwork (E) toward an ally to protect them or escape: the dash goes much farther, and you both gain a shield.

Knock your target into a wall with All Out (R): they go through it, you follow, and you hit harder at the cost of some of your health and resistances.

Take a short trade, then back off: Relentless Assault (passive) increases his attack speed with each consecutive auto.

During Counter Strike (E), back off instead of attacking: he dodges your autos, then stuns nearby enemies, dealing more damage per dodged auto.

Trade right after Counter Strike (E): it's both his defense and his only stun, and it has a 17 to 9 second cooldown.

In the late game, don't leave his split push unanswered: send someone to hold his lane, or force an objective on the other side of the map.