Teamwork seems to get it's stock raised cycle by cycle.
In RoRS and Kang, we saw the increase of Retaliate on Villains and minions, and so consolidating your attack power reducing the amount of retaliate damage you'll take.
In GMW, a couple of the scenarios encourage you to keep Allies into play by punishing chump blocking, so this easily extends their life.
Giant Man in general also loves to be paired with this card as keeping his health high keeps his Str at 4
For folks who blew this card off a year ago, they really need to give it another look