https://www.buick.com/build-and-price
From your linky - GM says they assemble the Cascada in Poland - from my linky WITH the 2.5% US tariff it runs about $33,000 to $37,000.
They say the Regal is made in Germany and it currently runs from $29,000 to about $37,000.
The Cascada would run about $35,500 to $39,700 and the Regal would run about $31,200 with a 10% US tariff.
I'm certain there are millions and millions of Americans who won't be able to buy or lease a new Cascada or Regal at those exorbitant new prices.