In the tweet, Panay shows an image of what appears to be two displays side-by-side in a "book-style" picture frame format. Given the text of the tweet, the displays are manufactured by LG Display, which is a common supplier of panels for smartphones, tablets, notebooks, and monitors (among other devices). There's not much else to the tweet, but we find it rather curious that Panay would post such an image given all the speculation surrounding Andromeda.
With that being said, a separate report from The Verge confirms the existence of Andromeda. The publication says that it obtained internal Microsoft documentation that references the "pocketable" Surface device. The document reportedly says that the device represents a "device form factor that brings together innovative new hardware and software experiences to create a truly personal and versatile computing experience" and that it will be "new and disruptive".
It's said that the device will have a stylus for taking notes and drawing on the displays, and in its current form looks very similar to the concept renders that were released in late 2017:
Microsoft goes on to say in the document that Andromeda will "blur the lines between mobile and stationary computing" and is destined to serve as a design prototype that will spur similar devices from other traditional OEMs. So, in essence, think of Andromeda as being like the original Surface, which helped breathe life into the Windows convertible market.