Device flow is an OAuth2.0 extension that expands the range of devices an organization can use within their overall digital customer experience solution to include devices with limited user input capabilities (such as smart TVs which do not have keyboards). With device flow support, users can leverage other devices, such as smartphones, to complete the login on the limited input device.

Blogs:
https://medium.com/identity-beyond-borders/device-flow-for-input-constrained-devices-4b8c993e4b87