I have a Samsung Odyssey Neo G9 monitor which basically does this. It basically has a simple KVM built into it. So my keyboard and mouse connect to the monitor, but then the monitor is connected to my desktop and a laptop. Using the monitor controls, I select which system I am using and get the display for that system as well as the keyboard/mouse activated for that system. There are different options for having them both on screen at once, but only one active for the controls, but I don't find that as useful as just having one system at a time being the sole focus.