Learned today my lawyer is under legal investigation for fraud. What happens to my suit if loses license

If your attorney has filed a lawsuit on your behalf and loses his or her license to practice, you would simply have your new attorney file a motion to substitute counsel and a notice of appearance in your case. Under the circumstances, the court would grant your motion and likely allow sufficient time for your new attorney to get up to speed in the case if it is been set for trial.   I do not know how far into the litigation process your case is, but if you have concerns of your own regarding your attorney, you should look for another attorney as soon as possible.