Facebook introduced a feature called Trending in 2014, and you can probably guess what it did even if you never touch Facebook. Yes, it shows trending news stories. Facebook is done with Trending, though. The company says it's killing that feature next week in order to focus on other news features.
Facebook has occasionally gotten in trouble because of Trending, which could get confused and surface objectionable content and Fake NewsTM. Facebook says it only rolled Trends out in five countries, and it only accounted for about 1.5% of clicks for news sites. It'll be visible as an expandable block next to your main feed if you have it.
So, Trending will go away (it's probably visible as a block off to the side of your feed on desktop) next week. In addition, the Trends API and any third-party apps that use it will stop working. In its place, Facebook plans to focus on a number of news initiatives that it already announced. For example, it's working with publishers to implement breaking labels, and there's the upcoming news content in Watch.