(For Treacherous Ground vs Firing Line). When you want to Ulti, try dropping Warder's Field first, to try and bait Khan into using his Shout. Once he's used it, wait 4-5 seconds, and then Ulti once the CC immunity has worn off.
If you suspect Mal'Damba has his ult ready, try to space yourself a bit from the rest of your team. Dread Serpent will knock you out of the air if you're flying, and its hitbox persists for a few seconds after it triggers.
Grumpy Bomb combined with Demolition legendary is a nightmare for Barik, especially if he's with another front liner. That's because he likes to set himself up in one place, and you are forcing him out every 10 seconds.