In the last movie Thanos was planning to completely remade the whole universe (by erasing this old one). So Ironman has tecnically saved the whole universe.

Oh snap!

Saved the other half from a big headache. Nobody wants to come in to work because the other half of the universe can’t make their shift.

Hulk was the one that brought everybody back. Ironman did away with Thanos to prevent it happening again.