Looks like Chessmaster is no longer sold in retail.
You can download a trial version of Chessmaster 10 (but full install I think) here: chessmaster-10th-edition.en.softonic.com/
I would presume there is a way to upgrade to the non-trial version. I already have Chessmaster: Grandmaster, so I really can’t check.
Still hands down a great teaching program for beginners and sub 1200 players. Still lessons for higher rated players, but a much higher ratio of lessons for lower level players.
Sad that Ubisoft doesn’t do a digital download of Chessmaster from it’s website.