The Joker has already been introduced in the DCCU and it is pretty cool! Joker has done some pretty messed up things to Batman and his allies over the years. One of them include something that occurred in the "A Death in the Family" storyline. The Batman V Superman trailer shows a glimpse of that moment.
Here as you can see:
Bruce has Robin's burnt suit displayed in the Batcave and it has writing on it:
HAHAHA JOKE'S ON YOU BATMAN
This grim detail shows that Red Hood could pop up in a future Batman movie.