What's the difference between Husky brand and HDX brand?
Marketing-wise, I'd say it's similar between Sears and KMart; same company with some same products but different markets. HDX covers a larger market-share, they have trash bags to storage to tools where Husky is almost exclusively tools.
Product-wise, Husky is trying to compete with Craftsman(Sears) and Kobalt(Lowes) offering lifetime warranties where HDX products do not.

Husky &amp; HDX are two separate brands, Husky hand tools have a lifetime
warranty and HDX does not, but is a more affordable house brand of
tools we sell now.
--The Home Depot Customer Care

--Source