The answer is in RELATIVE SCALES.

Each minor scale has a relative Major.
For example "A minor" and "C Major" are relative scales.
(A-B-C-D-E-F-G-A.) (C-D-E-F-G-A-B-C)

And so are "A minor Pentatonic" and "C Major Pentatonic"
(A-C-D-E-G) (C-D-E-G-A)

Now here is the "A minor Blues" and its major relative; wich is the key of "C"
(A-C-D-D#-E-G) (C-D-D#-E-G-A)

So, if you are playing a song in the key of "C major"; go ahead and use the
"Major Pentatonic Scale" or the "Major Blues Scale"= (C-D-D#-E-G-A)
They sound good when played over a Major Seventh chord.

It kills me when people say... blues pentatonic...
Pentatonic means Five. And the Blues Scale has Six Notes, therefore it cannot be called pentatonic.
However, you can use the pentatonic scale to play blues. Just don`t call it
blues pentatonic.

You gotta love the chromatic sound (D-D#-E) on the Blues Scale.

By the way you can play any of the minor scales listed above, over a
"C Major chord" since they have the same notes as their relative."C Major"