Common descent means that all living things are related by descent, just as you are related to your parents.
This gets messy at the microbe level because single celled organisms tend to share DNA rather promiscuously. It’s also true that a good portion of our (and most living thing’s) genome consists of viruses that have infected our ancestor’s germ cells and stayed along for the ride. You can track the history of these infections in the genomes of our distant (living) cousins. It’s one of the strongest lines of evidence that we are actually related to other creatures and not just sharing a common design.
You asked for an ID proponent who accepts common descent. Michael Behe will do. He’s the only person the ID movement thought was qualified to represent their side at the Dover trial. But he’s not alone. Check out the web sites uncommondescent and telicthoughts.
Even answeringenesis accepts common descent to the level of Family. I don’t know how they work out the details, because apes, including ourselves, are a biological Family.