According to Esri, ArcGIS Pro is not a replacement for ArcGIS For Desktop and both can to be used side by side. I tried migrating/importing Map Document, etc. to ArcGIS Pro but I do not see the same from ArcGIS Pro to ArcGIS for Desktop.
As there are some tools that are currently only available in ArcGIS for Desktop, I can foresee myself going back to ArcMap to do some of my work.
I do not see a way of opening ArcGIS Pro in ArcMap. ArcGIS Pro will create an extension of .mplx for Map Package (for example) and ArcMap will not be able to open it.
Is there a way to open the Projects or Maps save/created in ArcGIS Pro in ArcGIS for Desktop?
Best Answer
No. The Common Questions for ArcGIS Pro says:
Although it does not explicitly say that ArcGIS Pro maps cannot be opened in ArcMap that is the consequence of "Projects are not backward compatible".
The ArcGIS Pro Help says something similar: