The big plot twist in Movie 4 is that Shadow will be the one to cuck Silver out of the movies
>He's confirmed alive thanks to the post credits
>Chaos Control can time travel which means he will be ferrying the characters across timelines
>he is immortal so he can become a guardian of time while the rest of the cast dies out
All of this leads into his solo title movie where he uses his Chaos Control powers to travel across time and save the world.