In addition to everyone already left over from previous films, this one adds Wesley Snipes, Harrison Ford, Mel Gibson, Antonio Banderas, and MMA fighter Ronda Rousey.
Because action movies loaded with cameos and Mel Gibson as the villain never go wrong...
Seriously, the Expendables films are pretty objectively terrible - the first one had such bad editing that I still don't know how Steve Austin's character died, and the last one had shots that weren't even in focus. And yet I keep watching...mainly because I enjoy seeing Dolph Lundgren play a crazy person.
The teaser's pretty straightforward, and crowded as all hell.