I have seen various claims that Vista, Windows 7, Windows 8, etc are not members of the NT family, that they are something completely new. This is false. Windows 10 is very much a member of the NT family and in fact the core concepts (and many of the details) of it's operation haven't changed all that much since NT (3.1) was released in 1993. This is needful. It would be very difficult to design something that was really new and yet maintain compatibility with the existing application base. A new OS that doesn't maintain this compatibility would be a very hard sell.
And NT wasn't really new either, being based on VMS, a popular mainframe OS of the 1980's. And it was based on systems that preceded it.
Windows 9x isn't a member of the NT family but shares much with it. The primary design goal of Windows 95 was to be able to run most 32 bit NT applications and still maintain full compatibility with the older 16 bit applications. NT supported only well behaved 16 bit applications and many were not.
Linux and the Mac OS are not based on NT but they have much in common.