Most turn-based bots are in some way derived from minimax— you peer down the road looking at the space of possible moves and evaluate them based on an assumption that your opponent will respond with the strongest possible move available to them, so each move you can make now is only as good as the game state after the opponent's response, recursively.

I think basically as you're building up this tree you'd add annotations at each branch/ply which call out things the human user (opponent) could do that strengthen or weaken the position. Then as the human performs their actions, the tree is pruned/rebuilt accordingly.

Yes with Chess you can do exactly that no problem, but I bet Civ has a thousand heuristics woven through that which would make it horribly difficult. Maybe not impossible though!

The other complication is it isn't just 1 on 1, its 1 player vs ~10 players. So your move changes player 2's move changes player 3's move and so on.