Phil Spencer tweetet this earlier this week:

We are doing something we haven't done in awhile at Gamescom, it will be different from what fans expect but I'm excited.

— Phil Spencer (@XboxP3) August 16, 2017

Will he reveal an Age of Empires 4? Would be awesome!!

Is there any evidence at all to suggest it could be Age of Empires 4?

This is their biggest chance to make any sort of impact on xbox one x / s sales in europe so they really need to nail it. With sony still having showing in Paris and their playstation experience this is either a good start for microsoft sales during this holliday or a legendary bad year getting worse and worse

well the Xbox event could have some interesting stuff I doubt it will age of empires 4.

if its anything AoE related it would be the remaster being released on XBox One but as far as AoE goes, espcially in a year where they already had Halo Wars 2 and Halo Wars remastered and they both didn't do that great, is very unlikely indeed.

They need something else for sure.

I genuinely thought you were going to present evidence that suggested that it was indeed Age IV, but the tweet doesn't point out to anything, maybe the way they're going to present their stuff.

Haha, why does that suggest AoE 4 of all things to you?
Interesting to see what it actually is, of course.

They did just remaster Age of Empires 1 so there is a slight possibility

no they are STILL working on a re release of AoE that will release soon and is currently in beta so AoE 4 makes no sense lol
They also CLOSED the developer who originally made the series so who would be making it lol.

In an alternate reality maybe. But even that i doubt.