Tomorrow, on May 22nd, Stellaris will be getting another major Story Pack - Distant Stars. As you might predict from the name alone, Distant Stars will be a discovery and exploration themed DLC that will have you venture into the deepest and darkest corners of space in order to search for anomalies, delve through ruins of long-forgotten civlizations, and maybe even befriend gigantic, space-faring 'critters'.
If you're curious about how all of this translates into actual gameplay, allow me to share with you the recently posted 'Feature Breakdown' video. It'll give you a pretty good idea of what the Distant Stars DLC is all about, and whether it's something you should be excited about or not. Have a gander:
You can learn a few more details, as well as grab yourself a copy of the DLC itself, by heading over to the official website. And just for good measure, I'll leave you with the original and fairly lengthy developer gameplay preview. As expected, the video is a little bit unfocused given that it's essentially a "let's play", but it should help answer any of the more specific questions you might have. Enjoy!