Books to Read with My Sister

My younger sister lives in a different state, and we agreed to read a book together so we can have something fun to text/call about. We're both early 20's, I'm an avid reader and she's recently dipped her toe back into reading. I know she recently read "It Ends With Us" and really liked it, but that is the exact opposite of my taste. I'm more of a Brandon Sanderson fantasy kind of guy, but I'm worried epic fantasy would bore her. We both love Stranger Things though, so that's a common thread. What books do you think we'd both like?