Lacerte has now provided info in the F1 Help to explain what checking this box does.

Select the box (or enter 1) to apply the Coronavirus Aid, Relief, and Economic Security (CARES) Act provisions to the individual return.

This checkbox will:

1. Suppress Form 461 – Limitation on Business Losses
2. Update Form 8990 - Limitation on Business Interest Expense Under Section 163(j) from 30% to 50% limit
3. Generate critical diagnostic to remove “Carryover absorbed in 2019 [O]” from Net Operating Loss input screen to suspend the 80% of taxable income limitation on the use of NOLs.