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.
Standardization always seems to be a problem. Heck look at temperature readings around the world people still can not standardize Celsius or Fahrenheit as the reporting number for temperature. In Fahrenheit land 98.6 is normal for a body temperature, I have no clue what the standard temperature is for a body in Luxembourg or Egypt.