2. It Has Almost Nothing To Do With The Original Secret Wars
This isn't the first time Marvel have done a limited series called Secret Wars. As Hickman alluded to in naming his own comic after the publisher's first Great Event,
the original Secret Wars was the first proper crossover, universe-altering epic series that Marvel ever did, with the various superheroes and villains plopped on a different planet to fight each other. The in-universe explanation for this giant brawl was a cosmic being called The Beyonder, who wanted them to fight for his favour. In real life, it's because Marvel were going to make a toy line that tied into the series and make millions! Which means that The Beyonder was essentially the big kid who would buy all these toys and make them fight. So meta. This new Secret Wars doesn't have much to do with the old one - since that was quickly resolved and involved no alternate realities or reboots at the end - but it does share a couple of characteristics. For one, the name of Battleworld came from the alien planet where everybody fought last time; for another, it turns out there's a whole race of Beyonders, and they might be behind this whole thing.