Original Timeline
The universe as it currently exists is the result of Stephen Strange using the Time Stone to send the consciousness of Tony Stark back in time to 2008 with his memories in tact.
The actions of Stark caused cascading changes which lead to considerable differences between the current timeline, and the original timeline.
Changes include the fact that Pietro Maximoff is alive, the existence of the Savage Land, the incursion of the Beyonder into this reality, the existence of Providence Island, and the fact that Frigga is All-Mother of Asgard rather than Odin.