Try to separate him from his turrets and wait out his shield because of the short duration of the shield. Do not let him be first on point and set up turrets.
Slither cancels Hunter's Mark. Giving your position as a healer is bad, so it may be a good idea to slither away to get rid of it. You can still heal your teammates from a distance!
Your shadow travel can make you immune to everything. Use it to cancel ultimates and abilities, or use it in sticky situations. (I recommend using veil since it can make you go into shadow travel faster.)
If enemy Talus isn't using Faustian Bargain legendary, after finding his rune, it's guaranteed he's going to teleport here after a couple of seconds. Use it to your advantage, when confronting him.