DE's official stance on account transfer as of right now:
Q: Can I move my Playstation / Xbox One / Nintendo Switch account to PC? Can I move my PC account to Playstation / Xbox One / Nintendo Switch?
A: Warframe accounts can’t be transferred between platforms. There are technical barriers that prevent us from being able to move accounts between console and PC. In the past, we offered account migration between PC and PS4. We later did the same for PC to Xbox One and PC to Nintendo Switch. In those cases, we were able to work with different companies to make account migration available for a limited time in celebration of Warframe’s launch on new platforms, but account migration is not available regularly.
We don’t have plans to make account migration available again in the future, but you are welcome to start another account! We don’t have any problem with players having accounts on multiple platforms.
Q: Why doesn’t Warframe offer cross-platform play?
A: The differences between platforms prevent us from offering cross-platform play. The updates between PC and console don’t align, for example. There are also differences between items on Xbox One, PS4, and Nintendo Switch. With these nuances in mind, we don’t have any plans to offer cross-platform play in the future.