I see a very large majority of people online and social media under review and the large majority of them filed with TurboTax. Don't give me some generic answer either. I've heard from a few that TT didn't submit all the info correctly on their returns. ANSWERS PLEASE!
Only the IRS knows why they select the returns they do for a review.
In order to determine the exact reason, you will need to contact the IRS to see why your return was selected for a review.
The IRS reviews tax returns for many reasons including totally random checks.
Since in 2018 studies shows that TurboTax had 70% of the online do-it-yourself tax market, it only stands to reason that the vast majority of people that the IRS checks used TurboTax, even if totally random.
Heck, when 2 out of 3 people use TurboTax then TurboTax customers should be checked more often - if they were not, then the IRS would be accuses of favoring TurboTax customers :).