I second the response for Disk Drill or another third-party data recovery program, though it might be too late and SSDs are harder to recover from than HDDs. What I will say as an additional recommendation is to do absolutely nothing with the system that needs data recovery. This might go without saying, but the fewer changes you make to the disk the more likely you are to be able to recover the data. Don't even reinstall the OS if you haven't already, though that ship may have already sailed. When you use a program to try to recover the data, use a thunderbolt cable to mount the drive in "Target Disk Mode" instead of running it on the computer itself.
As a last resort, you can use your judgement to decide how valuable the lost data is. There are companies that employ specialists for this, such as OnTrack. I only know of them because they're headquartered in the same state as me, but I'm sure there are others. Just keep in mind that these services are often prohibitively expensive (they'll quote you, but I wouldn't be surprised if it cost over a thousand dollars).
