A Listing for “Ninja Gaiden Trilogy” for PlayStation 4 and Switch has shown up at Hong Kong’s largest distributor site.
Both listings have since been removed, but a cached version of the Switch listing (which you can see here) is still available. This also includes a link to the PlayStation 4 listing under the “New Products” section of the sidebar. According to the description, this collection contains Ninja Gaiden Sigma, Ninja Gaiden Sigma 2, and Ninja Gaiden 3: Razor’s Edge.
The price point is mentioned at $39.99 and the release window will be March 2021
No official announcement has been made yet.