Lee Sin will be trying to gank as much as he can in the early game. Keep this in mind and expect him to be all over the map.
If you meet Lee Sin in the early game, make sure you dodge his Q if possible. If he is able to land it, he will probably outduel you. Try to disengage if he lands his Q, or engage if he misses it.
Lee can easily secure objectives like the Dragon or Rift Herald on his own. Try and keep those objectives warded when they’re up, or try to take them before he gets a chance.
Lee Sin may try to kick R somebody like the ADC into his teammates. Group close together to make it harder for him to kick a carry into the arms of his team.
As Lee Sin needs to get onto someone in order to kick them towards his team, locking him down with CC as soon as he engages is ideal as he is rather squishy and will be unable to escape if he’s CC chained.
Lee Sin is really good at taking down or picking off isolated targets. Make sure you group closer to your team to make it harder for him to take anyone down whose alone.
Lee Sin will be trying to gank as often as he can in the early game. He is a strong duelist and will look to abuse his early game strength.
Once Lee Sin is level 6, his kill pressure intensifies as his Ultimate R can be used to set up ganks or finish enemies off. He is very strong at level 6.
As soon as Lee Sin has completed his jungling item, his kill pressure will be very high as he will have lower cooldowns and more damage.