According to Doug Lynch at xda-developers.com:
Android TV owners recently received an update across multiple platforms that have started to display sponsored content with a "Promotional Channels' title in the launcher of the Android TV software. We're currently seeing reports that it has shown up in Sony smart TVs, the Mi Box 3 from Xiaomi, NVIDIA Shield TV, and others. This has been an incredibly off-putting change for a lot of Android TV users. What makes matters worse is people were unable to disable the ads at first, but Reddit user Felisens seems to have figured out how to disable them.
[...] Update: Google's response
A Google spokesperson gave us the following statement:
Android TV is committed to optimizing and personalizing the entertainment experience at home. As we explore new opportunities to engage the user community, we're running a pilot program to surface sponsored content on the Android TV home screen.
(Score: 0) by Anonymous Coward on Friday April 05 2019, @03:11PM
Younger people still laugh at me when I say this.
There's always some chic Indian guy who has parents that are lawyers or are in IT that updates everything and has no idea how it really works. usually he leads the pack of laughing at simpletons like me that is clinging to something that still works when he's got two or three phones he can't decide between because they all have things he doesnt like but continues to buy high end marketing devices anyway because its cool or something.