The axe revived Thor, and thanks to its ability to channel dimensional energy to create a Bifrost bridge, Thor, Rocket Raccoon and Groot were able to travel to Earth instantly and help turn the tide in the Battle of Wakanda.
Thor nearly died making this happen, but thanks to Groot using his own arm as an improvised handle, Stormbreaker was created.
Despite Eitri’s initial hesitance, Thor convinced the dwarf to help him build a new weapon, which required re-igniting the true Nidavellir, a dying neutron star, so that the forge could be powered.