Of course Linux is going to keep going on - it's an open-source project after all! Linus Torvalds is on "hiatus" for the remainder of the 4.19 cycle but he should be back for the 4.20/5.0 cycle. Greg Kroah-Hartman is handling the rest of the 4.19 cycle, and he's more than capable of handling it while Linus is on hiatus. While I'm not going to go into the details why he's taking a hiatus or why Linux adopted a code of conduct or put on my tinfoil hat to speculate why all this is happening, I will say that it's pretty surprising to see Linus suddenly do this. Over the years Linus has come off as a bit abrasive at times when speaking his mind (his comments about Nvidia are legendary) so him learning to deal with others' opinions without getting into arguments might be a good thing. That's said, ultimately I think that's he's the type of person who's very passionate about his work however like I said I don't see the point to get into it more deeply. Let's just wait and see what happens after Linus comes back.
Microsoft couldn't take down Linux even if they wanted to. It's VERY hard, if not impossible to kill an open-source project as big and important as Linux is. Microsoft has plenty of problems on their own; slowly killing Windows in the perception of users' minds with showstopper bugs and lack of proper QA testing.