That indicates that the app is just trialing the 'Recommend' button with some accounts and it's not a confirmed feature yet. However, it appears as though the button lets you recommend videos to your followers. If you recommend a video, the clip presumably then appears on their For You Page as a recommended video.
How does TikTok know everything about you?
TikTok knows the device you are using, your location, IP address, search history, the content of your messages, what you're viewing and for how long. It also collects device identifiers to track your interactions with advertisers. In the US, TikTok can collect biometric information including face and voiceprints.