Content Adaptive Brightness Control (CABC) is a technology that is used to help to improve the battery life of laptops by dynamically changing your screen's brightness and contrast. As CABC changes the computer brightness automatically, depending on the content that you are watching, users find it distracting and annoying.
Based on the feedback from the Windows Insiders, Microsoft has decided to provide you an option to disable the Content Adaptive Brightness Control from the Windows 10 Settings app. If you are running Windows 10 Build 21354 or higher, follow these steps to turn it off.