Photoshop/Lightroom Mobile: Edit in interoperability for iPad

I had tried your workflow, and retried it after reading your comment. LR creates a maximum size jpg to send to PS. That's not acceptable. One wants the raw (nef for Nikon) to go to PS and I can see no straightforward way to do that.

I tried to Export Original to files. Adobe Document Cloud is greyed out. I did manage to save to my Desktop folder (this is the desktop on my desktop mac) in Apple  iCloud Drive. PS on the iPad could not recognize the file (Unsupported File Format). PS on the desktop correctly opened it into Camera Raw as a nef file.

Conclusion is PS for the iPad does not have Camera Raw available. And there is no way to work around and do the equivalent of an "edit in" Photoshop from LR for iPad.

I sure hope this is on the short range radar and that they can swing some iOS expertise back to LR for iPad as improvements are getting delayed badly on iOS apparently I would guess while the PS for iPad development gets priority.

I would add that even ignoring the LR integration with PS on the iPad issue, there is a grossly missing ability in the new PS for iPad to read and edit raw files directly from the Apple's iOS file system which had been imported from a camera or storage card.

To be the "world's best imaging and graphic design software" it must be able to work with RAW.  Why do I even have to state this?  

Integration will require work from both teams, and the Photoshop team have been... you know, a little bit busy building Photoshop.

Round tripping to/from Lightroom will absolutely be an amazing workflow, which gets my vote 100%, but PS is 1.0 and LR users are only a part of their audience. If they waited until it could do all the stuff we wanted to do, it wouldn't ship for years. This is just a start, and a great feature request to start gathering votes. 

Adding psd as a format option in LR for iPad export would allow a work around as one can export in psd from PS for iPad to iOS files someplace and then import back into LR.
  
So this is a temporary fix that could be implemented by the LR team, but all external evidence of very slow improvements to LR for iPad suggests that their iOS expertise is helping out on PS these days.

Lightroom should not send the raw file to Photoshop on iPad(this is what Lightroom Classic does on Win/Mac) - this will require camera raw with xmp files integrated in Photoshop for iPad which will take time.
Lightroom for iPad should send 16 bit/Pro Photo RGB tiff much like Lightroom for Mac/Win does now when "Edit in Photoshop" is clicked. This functionality is already in Lightroom(not classic), it needs to be enabled on the iPad version. I've checked and Photoshop for iPad has no problem working with 16 bit/Pro Photo RGB files - I've exported a raw file using Lightroom Mac/Win to Photoshop using "Edit in Photoshop" and stored it as a Cloud PSD. Then Photoshop on iPad opened and edited the file successfully.
As a very first version this will be great, we most probably don't need a way to return this file to Lightroom, though it will be great to have both the raws and psdc files in the Lightroom albums.
This should have being there yesterday - now Photoshop for iPad is simply useless for photographers and creates a huge frustration. We understand that there won't be all the filters and adjustment layers in version 1.0 but not being able to start editing 16 bit tiffs is a real deal breaker and disappointing.

@Thomas, don't worry, PS for iPad is a separate team. When a release seems unusually quiet, it's usually because the LR team are working on something that takes more than one release cycle to accomplish.

Export options just came to Android, so when they make it to iOS (likely next release), that'll give us the ability to output the 16 bit TIFF's you desire to send to PS. Maybe they'll even get the direct integration done by then.

This is some weird logic and miss management. So we have to wait a few more months, thus photoshop for iPad is not coming in 2019. nice.

Roundtripping now! Yes!

It is possible, but not obvious or intuitive.

First in LR for iPad click ... in upper right, then click Select, then select image, then at bottom click Share, then click Export As, then choose tif as file type, then click check mark in upper right corner of dialog, then scroll far right in Apps display and click on ... icon labelled More, then under Suggestions, scroll down to click Copy to Photoshop, then enjoy PS.

In that last Apps dialog, you can click in upper right hand corner on Edit and then make Copy to Photoshop one of your favorites so it will appear near the front of the horizontal Apps display and save a couple of steps.

Soon, I am sure we will be able to accomplish all this with one seamless click from LR. Maybe even soon, we will have direct access to Camera Raw in PS and not have to convert to tif.

Fantastic help - Thank You!!!!