Alexa and Cortana are now BFFs you can use Alexa-enabled devices to talk to Cortana and vice versa. This feature was unveiled by Microsoft and Amazon at Microsofts BUILD developer conference, but was limited to beta testers. It is now available to a wider audience as a public preview. Note that this is available only in the US for now.
Heres how it works. Say you have an Amazon Echo. You can say Alexa, open Cortana and then ask her about your schedule, send an email and anything else the assistant can do. You can do multiple commands without having to say Open Cortana before each one.
And it works the other way around. On a Windows 10 PC you can say Hey Cortana, open Alexa and manage your Amazon shopping list or use any of the third-party Alexa skills.
Check out this live demo if youre still not sure how things work (weve fast-forwarded to the good part).
Currently, this cohabitation works on Echo speakers, Windows 10 devices and the Harman Kardon Invoke speaker. Support for iOS and Android is incoming.
Again, this is a preview version of the Alexa/Cortana integraion so not everything works, e.g. you cant ask Alexa to play an audiobook through Cortana. Microsoft and Amazon promise to iron out such things with time.