To filter for a query for the Yes/No check box entitled "PG Milestone", configure CQWP like this:
This is another one of those obvious-once-you-know-it but hard-to-find-an-answer-to questions: How to filter on a Yes/No check box using the content query web part.
The first search result I find using the search term "filter yes/no content query web part" is flat out wrong, so I thought I’d put this up there and see if it can replace the incorrect result in typical search results.
It’s quite easy: True values = "1" and false values do not equal "1" (pretty retro, actually).
In the above example, I created site column of type "Yes/No (checkbox)" named "PG Milestone". I added it to a doc library, uploaded a few documents, set the value for a couple and tested it.