Adobe has previewed Photoshop CC for iPad at its Adobe MAX conference and announced its availability for sometime in 2019. An Express version has previously been available but Adobe is billing this as the full Photoshop.
Adobe Photoshop CC for iPad is built on the same software core as Photoshop CC for Mac but has been redesigned for a modern touch experience. It includes the familiar Photoshop tools around the edges of the screen and is compatible with Apple Pencil.
The iPad version can open and edit Photoshop's PSD files and will be compatible with the new Cloud PSD format that allows you to continue editing a file where you left off on another device.
If you have a current Creative Cloud subscription that includes Photoshop CC on your Mac (or PC) then you will also get access to Photoshop CC for iPad when it is made available. No release date has been announced beyond 2019.
Adobe has not yet decided whether it will be available as a standalone purchase or subscription from the App store.