Final answer:
Calvin Klein is the American fashion brand that designed innovative 'boxer briefs' and designer jeans in the 1980s and is now owned by PVH.
Step-by-step explanation:
The American fashion brand that designed innovative 'boxer briefs' and designer jeans in the 1980s, and is now owned by PVH, is Calvin Klein. Calvin Klein became known for its iconic underwear designs, including the boxer briefs. The brand also gained popularity for its designer jeans, which became a fashion staple during the 80s.