After lot of psychological turmoil in the humans, later we could not even get the leadership going straight. Everyone was sick, physically mentally tortured for a whole generation passed, and we could not rely or trust anyone. Finally, after lot of iterations of give and take with skynet, we had to give them, at least 50 pc of us to skynet as consultants, to avoid any sudden invasion. At about that level or a bit more, skynet reduced its advances towards us considerbly. Future confrontations was on the cards but nothing too deep, nothing incredible like a victory, etc. So humans started developing their first underground bases, with the help of the consultants. The surface housed our elite snipers and trollers. They would survey and do reconossence, and keep building their army of spys and snipers.