Blues harmonica players only spend between 5-10% of the time on stage soloing. Therefore, it is important for every harmonica player once on stage to play tasteful accompaniment. That means sometimes playing something continuously while others might take a solo or sing, and adding to the sound. Never get in the way of the other musicians by creating counter-rhythms or stepping on another performer’s solo. Playing something at a lower volume underneath the rhythm section can add another level to the sound. Either using rhythmic or non-rhythmic chordal accompaniment, we can lay down something solid that the rest of the band can fall back on and enjoy playing over. Being very careful to control our volume is the best way to make other members of the band happy and want to play with us again. Using extreme repetition and/or creating a quiet layer within the music allows for the harp player to be playing all the time while actually adding something beneficial to the overall sound. Do you think playing accompaniment is Important? Do you enjoy doing it? I love it. I think it’s more fun then soloing.
Any examples (links)? 
If you listen to any classic Chicago blues harp players you will hear them. Start with Little Walter. . If you need more info I’m happy to post links.
I really enjoy being the harmonica equivalent of the rhythm guitar. You’ve just got to be careful about treading on the vocalist -but that doesn’t mean you can’t play while they’re singing.
100% agree. Dynamic control is everything. Must not step on anyone else, yet add to the whole.
If you can arrange in advance with the singer and others how to do it playing counterpoint on harmonica can work well, it takes a bit of care not to overlap but it makes for some interesting music. It works especially well on solo tuned and chromatic
Considerations as an accompaniest.
With Chicago southside blues (harmonica style bands) – Muddy, Jimmy Rodgers, etc. harmonica was integral to the sound. Constant backing fits the style. You might be playing behind a vocal part.
Chicago’s westside sound (tough economics, sparse bands, often 3-piece) – Freddy King, Magic Sam, Otis Rush, Jimmy Dawkins, Hound Dog Taylor, etc. harmonica wasn’t typically part of their sound.
If the band is guitar centric blues aka B.B. King, Albert King, Little Milton, Elmore James or similar you learn to do a lot of comping – playing the horn parts or piano fills. You don’t play over the vocals.
Never over the vocals especially if the vocalist gives you the side eye lol……yes I 100% Agree.
Definitely agree with you. This applies to any instrument in a band. Blend everything together until it’s time to be a little outstanding. Dynamics is the key factor here and, never use effects constantly. Good taste is something that is acquired and, cannot be bought. Just the right lick at the right time can be more entertaining than wailing all the time. If a musician of any kind does not learn to do this it can ruin any performance. Less is More!!!