Ekkos main source of damage comes from his Passive. Avoid letting him stack his Passive by dodging his Q and standing outside his E range.
Ekko will look to set up a W stun by walking out of vision. Be cautious of this and wait a few seconds after he appears again before trading with him.
Ekko will look to constantly push the wave with his Q. Punish him whenever he uses it for waveclear by engaging in trades.
Locking down Ekko in team fights will prevent him from using his Ultimate R to escape with. Keep track of his Ultimate R in fights as he can use it to either set up an escape or engage.
Keep vision in typical flanking spots as Ekko will try to set up an engage with his W from out of vision. If you see him running towards you, back up for a few seconds as he would have used his W.
When no team fights are occurring, Ekko will be looking to split push. Avoid leaving him alone in a side lane by making sure there is always someone matching him.
When Ekko hits level 9, his waveclear drastically increases. At this point in time, he will look to go collect CS from side lanes and split push. Send someone to match him in the side lane to prevent him from farming for free and taking turrets.
Once Ekko hits level 6, his kill pressure increases and he will look to go for kills. Respect his all in potential when his Ultimate R is up as he will use it to escape after a kill.
Ekkos biggest power spike is at two items (Protobelt and Lichbane). When he completes these items, he will become a one-shotting machine. Ensure there is vision around the map and do not walk in un-warded areas when you’re unsure where Ekko is.