Control TV based on external IO device?

We are looking at developing an app that will display a HDMI input with an image overlay on top of it but the overlay image will change based on some other external input (REST, UDP, etc). We’re looking at having an external controller turn on an input on a GPIO DAQ and somehow have the app monitor that input to change which overlay is being shown, similar to having a physical external button can change menu options on a kiosk.

We want to use something like this to be able to control the overlay: 16 Channel WiFi GPIO Module | Numato Lab Help Center

Is this possible?

Where do we start?