The M–sigma (or M–σ) relation is an empirical correlation between the stellar velocity dispersion σ of a galaxy bulge and the mass M of the supermassive black hole at its center.
Sort of. It depends on what you're asking exactly.
Massive Black-hole (MBH) mass and stellar velocity dispersion are two independent properties of a galaxy, which are observed to be related. Any galaxy (or bulge) that has stars (which is required for them to exist) can have a velocity dispersion. That being said, a MBH doesn't necessarily need to have a host-galaxy, and similarly a galaxy doesn't necessarily need to have a MBH*.
The observed $M-\sigma$ relation is usually interpreted to mean that somehow MBHs are able to effect their large-scale environments (i.e. their galaxy as a whole). The growing consensus is that the mechanism of this interaction is via 'Feedback', e.g. This paper by Fabian, or this pop-sci article. It is not interpreted to mean that the stars in the galaxy's bulge are physically orbiting the BH, and the dispersion is directly caused by that orbital velocity.
*Although, statistically it looks like basically all galaxies tend to have BHs.