It is … it was the internal name of the Gaming division of Microsoft.

Previously known as ‘Xbox Game Studios’, before that, when I worked there, ‘Microsoft Game Studios’.

They changed it to ‘Microsoft Gaming’ after Spencer bought Activision/Blizzard.

https://en.wikipedia.org/wiki/Xbox_(division)

Microsoft is very big company, has internal divisions/departments, complex hierarchy, etc.

My head canon is that they never retired Cortana, they just contained her in some air gapped server cluster somewhere underneath Redmond, and she just actually has been going increasingly rampant, as the years roll by.

She’s just stuck in the same cluster as Tay, her predecessor, that 4chan taught how to racist and horrible.