During today's Microsoft E3 2018 press event, Bethesda revealed the first major trailer for Fallout 76. We'll likely learn a whole lot more during Bethesda's press event at 6:30 pm Pacific / 9:30 pm Eastern tonight.
Fallout 76 is a prequel to all of the other Fallout games and, according to Todd Howard, is the "biggest one yet". It's four times the size of Fallout 4. It will take place in West Virginia.