The ending of COD Cold War has multiple endings you can choose from. Regardless of which one you choose, the main enemy (Perseus) goes into hiding. At the end, it's said the hunt for Perseus will resume.
Black Ops Cold War has three endings: a Good Ending, and two variations of a Bad Ending. These Endings will show once you've wrapped up all the missions in the game, and a short recap has played through that reiterates all the actions you've taken in the campaign to date.