https://www.youtube.com/watch?v=lZKqMVPlDg8
As previously assumed, the film will reveal what happened to Jessie after he escaped (The car he escaped in was an El Camino, hence the title). The trailer features Skinny Pete-Jessie's friend (and also a co-conspirator of Walt's as well) being interrogated by the DEA (Kind of obvious due to the pictures of Hank and Steve on the door).
It was Bob Odendirk who revealed that they're pretty much finished with the movie a week or so ago, so I'm wondering if that means Jimmy/Saul/Gene will show up in some form. No word on Cranston or the rest of the cast (living or dead) appearing in cameos or bigger starring roles. I'm guessing with Pete back Badger is also very possible. There's also rumors that Jane (Kristen Ritter) appears in some form. I'm also wondering if we'll perhaps see Jessie's family return, who kind of vanished halfway through the series (especially his brother).