I believe the Vice President owns several sets of Alexander McQueen separates, including this ensemble in a color called ‘electric navy’ or electric blue.’ Here, you see her wearing them at a campaign rally in Milwaukee during the Democratic National Convention.
The jacket appears to be a classic Alexander McQueen style, the brand’s Peak Shoulder Leaf Crepe Jacket (originally $2590). The tailored style is a viscose/acetate blend and features some of the brand’s signature design elements, like the sharply angled pockets. It also has padded and slightly raised shoulders, peaked lapels, and a single-button front closure.
I am not 100% convinced these trousers are identical to the pair worn by Vice President Harris, but they are at least close in design. The Pleat Front Trousers ($939) are the same viscose/acetate fabric blend and feature a front fly, two front pockets, and one back pocket.