We already know that one Shenmue game is in production, and that's reason enough to be satisfied. But there might even be a second one.
SEGA of Europe has registered the ShenmueHD.com domain, as indicated by WhoIsSearch. If it's a real production, then Shenmue HD would be the first SEGA Dreamcast title to receive a remaster.
The HD title is usually representative of remasters for Xbox One and PS4 which offer the original game experience with increased visual fidelity.
In some cases domains are registered in order to prevent another entity from owning the URL, in which case production isn't yet set in stone. As such, this isn't confirmation of Shenmue HD, but does introduce the surprising probability.
Shenmue 3 is currently in the mid-stages of development with an anticipated release window of December 2017. Its latest screenshots and a progress update can be seen here.