Defending champ Brigid Kosgei is back, but Jordan Hasay is the only other woman faster than 2:22:56. Boston champ Lawrence Cherono & Dubai champ Getaneh Molla join Mo Farah & Galen Rupp in the men's race. And Amy Cragg is a scratch.
Kosgei comes in as the defending champion after winning in 2018 in 2:18:35 and then winning London in 2:18:20. She is joined by Betsy Saina (2:22:56) and Mexico's Madai Perez (2:22:59). Chumba won Chicago in 2015, but will only be the fourth fastest in the field as Dubai champ Getaneh Molla (2:03:34) and runner-up Herpasa Negasa (2:03:40) lead the way along with previously announced Mo Farah. USA's Amy Cragg, Chris Derrick and Brogan Austin have all withdrawn.
Rai Benjamin and Karsten Warholm square off for the first time in the men's 400 hurdles while Dalilah Muhammad faces Sydney McLaughlin in the women's 400 hurdles. Plus a battle of WR holders in the women's 1500 and Justin Gatlin vs. Noah Lyles in the men's 100.