Super Smash Bros. All-out! is the 5th game in the SSB series. It is confirmed to come out July 17th, 2018.
In SSBAO, the battling is much less Brawl and a lot more Melee. There also some smaller changes, like a pushing mechanic and a new Smash attack, behind smash.
There will be over 70 playable fighters in SSBAO (not including DLC). 40 Are already unlocked and the other 30 needs to be unlocked through specific actions. To see there moveset, go here.