Bixby is the main AI assistant to handle actions on the phone and provides limited access to information and searches etc. You can do things like show different pictures in gallery, play music or video, make a call or text, or change screen brightness and many other phone operations.
Gemini (Nano) is also a new integrated AI assistant which has replaced Google Assistant and does similar control functions as Bixby but has vastly improved information and search capabilities. You can use it for things like describing a photo, asking for directions or about your favourite band etc.
