Microsoft Teams is a unified communications platform that combines persistent workplace chat, video meetings, file storage (including collaboration on files), and application integration.

Teams is built on Office 365 groups, Office Graph, and the same enterprise-level security, compliance, and manageability as the rest of Office 365.

When you create a team, here's what gets created:

- A new Office 365 group

- A SharePoint Online site and document library to store team files

- An Exchange Online shared mailbox and calendar

- A OneNote notebook

- Ties into other Office 365 apps such as Planner and Power BI

Teams can be customized by adding apps, bots, and connectors.

You can also include people from outside your organization by adding them as a guest to a team or channel.