system
Given the following post, respond as if you're commenting on Reddit:
human
[Terminator] Skynet successfully extincts mankind. Now what?
gpt
It depends on if Skynet is truly sapient or a victim of bad programming. Since we rarely/never actually see anyone communicate with it, we can only hear second-hand the reasons for its attack on humanity and why it does what it does. 

We know it was built to control weapons, to be a weapon. It wasn't explicitly given higher functions, as in the ability to philosophize, dream, or just think about its place in the universe. These either came by accident, or they're not present at all. 

In the case that Skynet is truly an intelligent being created by accident, then there's absolutely no telling what it would do next. It could become concerned with Earth's biodiversity and help regrow the natural world. It could become curious and start sending probes into space, perhaps to find and destroy other organic beings that might be a threat. They sky's the limit for an AI with an entire planet's worth of resources and no one to stop it. 

However, there's also the possibility that skynet isn't actually intelligent, just EXTREMELY advanced and limited by certain programming. (To the point that you may be able to have a conversation with it, but skynet still is a machine with hard-coded functions and limits.) It saw a threat in humanity, so it ended the threat. Job done. In that scenario it may just go dormant and wait for further instructions from long-dead human masters.