I feel like with all the cheating in this game, there should be an archive of what cheats exist. I'll start with what I've seen, and edit this post as more are commented.
Aimbot) The basic cheat, aims for you. This cheat can be spotted by kill cams. Sometimes people do have freakishly good aim, and the way to distinguish here is that people with good aim do miss, and their aim is kind of Shakey. Also they will ads and hipfire appropriately, not preferring one over another. Actual aimbots normally only hipfire, since the in accuracy will help them avoid suspicion. Also aimbots will land shots and track targets that should not be possible, like dmr headshotting someone while stimming and flying across the map. They will do this consistently as well. The fix is to just get the drop on them or use unfair tactics, like phase shift and shotgun, or arc grenade since it limits their camera turning significantly.
Wallhack) also another basic cheat, this gives the hackers instant knowledge of where players are, whether or not they can have that info. Just yesterday there was an enemy legion tracking my head through a wall, except that k spawned there and cloaked immediately. Didn't matter in the face of hackers though. The only way to avoid this kind is to not play, and it also normally goes hand in hand with aimbot.
Position lies) so I'm not sure what to call this, but there was someone yesterday in my game where his visual was where he percieved, but his hitbox was a solid 10 seconds behind him. Really weird, this one. Anyone else seen it?
Lag switching) looks like teleportation, but in reality it's just coordinated lag. The only way it appears to counter this is fight them like a normal player and hope that they're bad on their end. They can still die, but it's harder to kill them.
How many did I miss?