Thing is chord progression can actually refer to one note, not necessarily chords.
See say your chord progression goes CEG, well those 3 don't have to be chords.
For example it could go C chord, to E note, to G chord and that would still technically be CEG, although you're not using all chords.
Some songs use only 1 chord, but it is not the norm.
An implied chord progression, if there is some kind of backing track besides drums and melody, say a bass part, is a chord progression.