The Supreme Court of Canada will not review a Québec ruling that bars Canadians from suing the U.S. Government over it's involvement in Project MKUltra
Ontario’s information watchdog is considering ‘potential next steps’ on alleged deleted Greenbelt emails
This other article provides further details.
https://www.cbc.ca/news/canada/montreal/mk-ultra-class-action-lawsuit-u-s-immunity-in-canada-1.6985475
Basically the 3 judged decided that the law that was passed in the 1983 couldn't be retroactively applied.
However the plaintiffs say it can since it was retroactively applied in other cases.