how is America's involvement in WW2 relevant to today?

Answer 1

What relevancies have you found?

Answer 2

I haven't found anything besides how women went into the armed forces and helped the country.

Answer 3

Women also went to work -- many for the first time outside the home.
Eventually Europe became unified.

More to come . . .

Answer 4

Antibiotics were developed.
The horrors of the Holocaust taught us "never again."
Aircraft was improved.
We learned of the dangers of nuclear weapons.