Hope this eventually makes its way to the internet. I wanna see this now!
https://www.mirror.co.uk/news/uk-news/lord-rings-director-peter-jackson-11898487
Wow - didn't expect WWI.
There have been some projects like this before in the past decade (including some projects featuring original color footage from French cameras). "The First World War" series (from the team behind "The World At War", iirc); and "Apocalypse WW1" both come instantly to mind.
No doubt PJ's will be more extensive in the digital cleaning and, um, hand-painting (not digital, but appropriate since that was one of the colorization processes for b/w film back then.) Plus however he scripts and edits it together.