Campaign budget optimization, or campaign budget optimization , manages your Facebook and Instagram ad campaign budget across ad sets automatically to generate the best overall results for the entire campaign. With CBO , you set one central campaign budget. This budget is allocated in real time during your campaign to the ad sets where the Facebook algorithm sees the best opportunities.
The image below clearly illustrates the difference between an "old-fashioned" ABO , or "ad set budget optimization" campaign, and a CBO campaign.