Apple began sending out invitations today for an event that the company will be holding on March 27 in Chicago. The invitation only says, "Let's take a field trip", and the event will focus on education.
As for what we might see at the event, you can certainly expect software, such as improvements to Apple's Classroom app. In fact, Classroom 2.2 has been in beta for some time, so March 27 might be the right time to announce that. There could also be new educational features that are going to arrive with iOS 11.3.
But it wouldn't be an Apple event if there's no new hardware. New iPads with Face ID and slimmer bezels have been rumored for a while, and with Apple's focus on productivity on the tablet, it could be perfect for an educational event. It's also about time for a refresh of the cheaper, non-Pro iPad.
Of course, there are still students who when asked "what's a computer", they still have the traditional answer of an actual laptop. We'll likely see some new MacBooks, and rumor has it that there's going to be a cheaper MacBook Air released this year. Lowering the barrier of entry to MacBooks would be a key move for Apple in continuing to penetrate the educational market.
What you shouldn't expect are new iPhones (or flagship ones, at least), Apple Watches, or Apple TVs. iPhones typically get launched in September, and the others have been refreshed too recently.