The tease comes from Geoff Keighley.

It looks like we may get an announcement of a Saints Row reboot next week at Gamescom 2021. The tease about the announcement came from Geoff Keighley, host of Gamescom Opening Night Live (and a bunch of other stuff throughout the year).

Keighley's tweet says that they are "'Bossing' it with our announcements this year." Included in the tweet is a link to SaintsRow.com. On the site an image is shown that simply says "Rebooting." I don't think you can get much more obvious than this that a Saints Row reboot is happening.

In 2019 THQ Nordic confirmed that a full Saints Row title was deep in development. An announcement was apparently planned to take place in 2020 but it was obviously postponed for whatever reason, probably COVID-19 related.