The 4 chord miracle of pop/rock music in C major is:
A min - A C E
F maj - F A C
C maj - C E G
G maj - G B D
With the pentatonic scale C D E G A, your odds of hitting a note that matches the chord is good, and your odds of being able to correct from a note that is just off... into a matching note and sound like you did it on purpose is also good! Hahaha! As for the Gmaj... it often likes to have "suspended" extra notes that bring it back to another chord anyway...

So yes, the pentatonic is the easiest way to improvise when you don't know exactly what is going on! Hahaha. I don't do much better than that with the occasional 4th note (F) thrown in most of the time... but I usually play alone and don't get to jam with other people much! Hopefully I improve that aspect of my playing with time, loop pedal and friends...