He is currently attached to the next Terminator and Universal hope to continue riding his wave of success, as Deadline report they have signed him for a two picture deal. One of the films pencilled into this deal will be the sixth Fast/Furious movie and the identity of the second film is currently up in the air.
The first possibility is Leading Man, a spy adventure based on the comic book by B. Clay Moore, about a famous Hollywood actor who moonlights as a successful career spy. A little corny but Lin can take corny and turn it into something legitimately thrilling, so I have no concerns if this turns out to be the film that follows FuriouSix (I'd seriously be willing to bet that's the title they go with).
The other possibility, however, is far more intriguing. This would be a WWII movie based on the 442nd Regimental Combat Team, an all Japanese-American unit who went on to become the most decorated regiment in the history of the US armed forces, with 21 Medal of Honor recipients to their name. This is the more interesting (and important) story to tell and it would be a nice way for Lin to branch out from the action blockbuster genre with a story with a lot of gravitas, as well as an opportunity to show off those finely tuned action chops. It might involve some "race-bending" but I imagine Lin would like to find a role for frequent collaborator and Fast/Furious fan favourite Sung Kang, despite his Korean origins.
Whatever comes next for Justin Lin, one thing is for certain: This guy is going places fast. And furious.