Another of the games that Microsoft offers for free in event X0 is the first Crackdown. It's Xbox360 but also backward compatible with Xbox One and with 4K support for Xbox One X. Unlike PUBG and PES 2019, which are free for the weekend, it looks like this game will remain free for gamers too .
Microsoft has not yet announced an official announcement, apparently everything will be heard tomorrow in the X0 evente.
Crackdown can be activated for free in the Xbox360 store.