When creating a world with which your friends will roleplay, it can be difficult to figure out something to do out of whole cloth. At the same time, sometimes there's just some things you really want to play out from television, a movie, book, or maybe even one of the increasingly popular actual play roleplaying shows on YouTube, Twitch, or offered as podcasts. Is it okay to pilfer these ideas for yourself, shifting them to fit the genre and system of your game? I say yes, yes it is.
The best form of flattery is imitation, right? In so long as you aren’t trying to sell the game you wrote based on someone else’s work as your own, then I see it in the same vein as other fan works, like fan fiction or art, honoring the original creators through your interpretations of the work.
That said, though, it might be best to pick something that is either more obscure, or at least something you know that your party hasn’t heard of, so that they don’t know what is coming. While The Empire Strikes Back is an amazing movie, making the big bad a dark paladin and enforcer of an evil emperor who surprises one of the characters by revealing that he’s their long lost father might be a little obvious.
But that is where your creative side can shine, in the taking the canonical content can changing things to how you think it should have gone. Maybe instead of Vader being a man, you can make that character female, or perhaps the emperor has a bigger role to play. Maybe everyone can be magical, and thus to varying degrees, everyone is Force sensitive. The more you alter the story, the more it becomes your own, and the better your chance to surprise your players with plot events.
So, while having your own story that you made completely will always be really cool, there is nothing at all wrong with taking from popular media to help your campaign along. You can always do this in a hidden manner, not telling your players that you took one plot from here and some NPCs from there, or just straight up tell them that you’re doing your take on the first The Mummy movie, and your party will be versions of Rick, Evie, and the rest. Either way, it could be fun.