Milos Raonic withdrew from Montreal and may never return to his home tournament.
Men's and women's champions will earn each $3.6 million, first-round comes with $100,000 pay day.
"We want to show how much we respect what Novak has accomplished, and also attract tourists,” Serbian President Aleksandar Vučić said.
Defending WTA Finals champion Iga Swiatek is first player to qualify for season-ending event.
A pair of former Grand Slam champions lead Cincinnati women's wild cards.
Moët & Chandon will be available at a number of locations throughout the US Open grounds this year.
Emma Raducanu shares ambitious aim.
