As far as I know, a movie based on Itachi Uchiha was about to come in March.
Can anyone please tell whether it's coming this year or is it delayed?
Here is a Reddit thread of the poster, and here is a YouTube video of the trailer:
The Itachi Shinden adaptation has already started airing via Naruto Shippuden episode 451 and onwards.
Crunchyroll notes that it began airing on March 3rd. Episode 451 aired on March 3rd and these episodes exactly follow the novels.
It is set to be aired until May.
This is not a movie. The Itachi Shinden novels are being adapted to a TV release, which will air this spring. I didn't see information about it beginning in March.
The Naruto twitter account shared a link to TV Tokyo Naruto website which has a small trailer and information about the release, which seems to indicate that it will begin airing in Japan on April 7th.