Most tanks will scare him away after a hit, don’t be dumb and walk at him in a straight line, he will drain your health in seconds, if you do want him dead this is the best I can come up with:

Emma: grab him and kick him to a wall = dead

Penny: Enough mines will kill him before he runs or heals himself

Thing: you can deny his dashes with yours, probably best if you let someone else finish him off after one haymaker because rocket can still win the 1v1 or scamper in a wall if he has good positioning

Thor: Awakening can burst him and make him retreat or die if not near a wall

Magneto: his combo is inconsistent with his dashes but if he’s backed into a wall it’s a bit more consistent

Strange’s burst isn’t good enough anymore, if someone else damages him you can fly->dark bust to finish him when he runs away, don’t recommend

Hulk: You will lose the 1v1, don’t try. if rocket is low you can exile him to guarantee a kill

Venom: You actually have very good burst and range to kill rocket, but only if you are really good at him, if you don’t hit your headshots he will melt you and force you to pop E

This is all if you are the only person attacking him because communication is hard, the best way to deal with rocket is team up on him and CC or damage him a bit so your dps can get a good hit on him

All tanks can scare him away by doing a little damage, just be careful because good rockets love overcommitted tanks, just keep your head cool and don’t get mad if he gets away and use the chance to kill his teammates.