"USA" is interesting.
If you read it as "United States of America", the article "the" is required.
"USA" has also taken on the status of a proper name, and as such, you would not normally use "the". My grammar checker is telling me it should have the article because it is a proper name, however, this reveals confusion about this matter. Most proper names do not use the article. So, whether or not you use the article depends on how you are thinking about the term, "USA". I say you do not use the article when you are thinking of the "entity" known as USA.
Grammarians will probably disagree, however.
Student or Learner