Introduced as an AssistiveTouch helper in the iPad's accessibility options, mouse support includes both wired and wireless gear, as well as the Magic Trackpad thingy of Apple. Once connected, the "cursor" won't look like a typical mouse one, of course, but rather a circle imitating a finger touch. Apple isn't listing the new option in its extensive new iPadOS features list, but it's there.
Remember, that's because it is an accessibility feature, but folks who have been waiting for a mouse and cursor support, any cursor, would nonetheless be glad this is happening. The new iPadOS aims to close the gap between tablets and laptops, and introducing mouse support is just one more arrow in Apple's quiver on the quest to do just that.