Overwatch's Halloween Terror brought players their first experience going against PVE opponents. Following that, the second Overwatch Archives event, Overwatch Retribution was the most recent PVE event in the game. These types are fun because they provide either, a different mechanic to the game, or give insight to a good amount of backstory for the heroes.
An Overwatch fan on Reddit posted their prediction for the next PVE event. User, CarryTreant predicts that the next setting will take place in Junkertown, involving Junkrat, Roadhog, Hammond, and Ana. Revealed as Hero 28, Wrecking Ball is the latest character introduced into the Overwatch universe.
CarryTreant's suggestion involves Junkertown's Arena and reads, "Junkrat, Roadhog, Hammond, and Ana (yes ana) facing off against the arena's best challenges, possibly with the hidden intention of stealing something of importance.
The post continues, "Ana at this point in time will still be 'Shrike', a mysterious bounty hunter. Hammond will also have a similar thing going on, disguising his true identity. It will be a window into what Ana got up to her in Shrike days as well as a great opportunity to show how exactly the misfits of Junkrat, Roadhog, and Hammond all end up involved in the broader story."
The theory is interesting because other than the one cinematic between Roadhog and Junkrat, there has not been much development for the two. The Junker Queen remains a mystery as well. Hammonds character introduction fits in with the history of Junkertown too.
The balance of these four heroes seems like it would be optimal for a PVE event. There are two tanks, one dps, and one healer to fulfill core roles.