From what I know, they have a small field around their crosshair, an outline. Anything in that field becomes target for aimbot, my guess would be that player characters are a priority but I could be wrong. If your character ends up in that field they aim draws towards your character body or pixels, something like aim assist only more powerful. Even very tiny part of your body showing is enough for it lock on.
The only way to outrun it is to use a stim, use cruz's speed ability, and having energy overflow skill equipped.
Here is how the tracking looks like:
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2652610884
Second important thing to know is that the hacker always knows your location. You can hide behind cover but visibly that will not hide you.
Third important thing to know is that the hacker never reloads, do not expect any breather room. Whatever gun that person is using will never stop firing.

Thankfully, like around 95% of those people are not smart or tricky in any way. They make it extremely obvious, because they are not even trying to hide it.
You must use combination of signs that I list below.

• One of the main giveaways is that their shots have no projectiles. So if you see someone shooting with a gun that has no projectiles leaving it, that person could be potentially a hacker. Potentially because you have to keep in mind that sometimes it is hard to spot projectiles from certain weapons like crossbolt and bows. Also sometimes, I believe there is a bug that is very similar, you just do not see the projectiles leaving weapon from certain person. So it is not a dead giveaway but something to look for.
  
• Second giveaway is they never reload. If you see someone using crossbolt like an assult rifle, yea no that is not how that weapon works.
  
• Third giveaway, the weapons they use often have either no sound or different sound than what it should be.
  
• Lastly, if hacker is a Kali, they do not lose their invisibility when shooting. That means, they go invisible, they shoot and stay invisible, at the end of Kali's ability duration they become visible again. So do not confuse it with known bug, where Kali is permanently invisible and you can only see her weapons. Those are two different things, one is a hacker, the other is just a player who is unaware that he is permanently invisible.

Those are the 4 easiest things to look for. Everything else is experience based. That means knowing, remembering and having a feeling for how each of the guns work. Remember, it is very disrespectful to accuse someone of hacking just by having a feeling that something is off or if someone pulled a skillful stunt. There are a lot of skilled players around. So be respectful to your fellow explorers and try to look for more distinct giveaways like those I mentioned.

Believe it or not, but most of them are no better than fighting an NPC you find in camps. They have very little awareness and they leave the hack to do all the work for them. They just move their character around and expect to win, this is exactly what we want. We want them to rely on the hack and not on their senses because that makes them dull and easy to fool.
First of all you must get yourself high burst damage weapon, especially if you solo this. Here is a list:
Rosie
Rosie Packrat
Rosie Sledgehammer
Rosie Guardian
Longstriker Taskmaster
Devastator
Boompipe
Devastator EXT
Devastator Corsac
Crossbolt

Once you got yourself one of these, try to avoid open areas as much as possible. Fighting a hacker in open area is pointless. Always move next to cover or somewhere where you can get to cover fast and try to spot the hacker.
When you spot him or if you know the area he is moving around, try to find a location with a lot of cover to fight him. Remember, hacker always sees you, so try to bait him close to that location. Best possible moment to bait such person to follow you is when he killed your teammate. That is the moment the hacker wants to finish you even more, so pretending that you are panicking or that you are scared works like a charm to get him where you want him. Always stay at the right side of cover and use your 3rd person vision to peek.
Once the hacker is close enough, do and repeat something I personally call a "peek-a-boo". That is when you come out of cover for tiny amount of time to shoot and get back behind cover. Do that correctly and you should be able to take hackers solo no problem.
If the hacker got in a position where you can't use cover do not bother dodging it wont work, spend all focus and energy on aiming and shooting.
If you can coordinate with teammates, do the above, only instead of doing this one by one do it all together at the same time. Hackers aimbot can't shoot 3 targets at the same time. If you have the opportunity to do it from different angles then even better.
After you defeat a hacker remember to give them the universal "gg well played"! Also remember to report them in game and on discord.

But Orome, how do you know this guy is a hacker?
His weapon makes no sound.
His weapon has no projectile.
He never reloaded though lets say I missed that.
His Kali did not drop invisibility when he was shooting, only after the duration of the ability ended he became visible (Pay attention to sounds).