Actually!

So combining MSC with cancer can be a bit risky, as they can boost the cancer, although people are trying to optimise them for use in cancer therapy. And MSC for lung fibrosis (aka scarred lungs) are already a thing! There's even a phase 1 clinical trial for using MSC to treat COVID.

The main problem is that because they can be derived from so many different tissues and because there is not really a standard for how to grow/use them, it's a bit hard to predict how and if they work in a patient.