As someone who has talked to Helion multiple times and we even had them testify before our Committee last Congress on fusion this is huge but not out of the blue.
Helion signed a power purchase agreement with Microsoft a couple of years ago and in that contract were some pretty strict and significant financial penalties if they did not deliver. Their system is also a significant departure from the commonly thought of Tokamak design (the donut) and instead is a linear fusion system which looks like this below.
They have been extremely secretive though and not a ton is known about the design or how it works compared to other systems esp. Why this one is so far ahead. That being said they are finishing up their 7th prototype that they hope by the end of this year will generate their first electrons. The contract with Microsoft give them through 2026.