An Office 365 group is a distribution list AND MORE! You not only get the full functionality of the original Distribution Group but a shared document library for storing and sharing folders and documents between members. There’s also a shared OneNote Notebook, useful for taking a project and meeting notes. And so everyone in the group stays on the same page, there’s also access to Microsoft Planner, a shared calendar and a shared inbox for assistance in scheduling group meetings and events! To see Office 365 groups in action, click here!
Teams are currently in Technical Preview right now (general availability is set to Q1 2017), but if you would like to activate it for your Office 365 tenant.