Skynet's nowhere near existing. Scratch that. Facebook Skynet's nowhere near being able to make decisions for itself.

Ok, yeah, technically it can, but only multiple choice. So unless somebody's stupid enough to give it the option of "eliminate humans" (and tell it how to do so), and then not just mess up its fitness function but deliberately program it with a goal that would end up eliminating humans (as opposed to enslaving us as like farms or whatever), and then train it on a supercomputer or two without anyone noticing… then we're fine.

But the nuclear button's easier to get your hands on – at least for the foreseeable future – so we're not going to die by Skynet any time soon.