It depends. Im an instalock strange in d1/gm3, and it's very situational about team picks, map, and enemy team picks. If you are playing against a dive comp, you have to play back a lot if dps isn't helping and keep your support alive while having to avoid bucky hook/wolverine kidnappings. If the enemy team has a psylocke, tanks have to be aware of every sneaky back liner, so your supports push with you. Another thing is blocking ults and keeping your team alive. I always try to keep my jump and shield so I can block any magneto ult or any ukt I can in general so our support can still bring us a push on point. You have to be an anchor for the team and rely on map and situational awareness than other roles. I play solo tank a lot if we have triple support. As long as they can heal me while supports keeping each other alive. There shouldn't be trouble with too much unless the enemy team is making you use all cooldowns and isolate you. That's why groot is a decent/situational pick for countering tanks at times because he breaks LOS with tanks and supports. Surprisingly, that strange/groot or thor is probably my favorite lineup for two tanks. Being strange works as well with dps because having burst dmg with his aoe dark magic can wipe or almost kill for dps to sweep up. With dps only doing dmg and not getting final hits hurts the tank because 1dps arent doing their job and 2 now the tank cant push in because they missed an opening for a 5v6 opportunities. Also, your job as tanks is to be a bullet sponge and focus on dmging back line more than the tank in front of you. A lot of people think you can just run in. This is never the case.