As reported by AFP, the current 3.000-meter Olympic champion, the Bahrain Ruth Jebet, has been suspended four years for EPO doping.
Provisionally suspended since 2018, it has been punished with four years and can't defend his title at the Olympics Tokyo 2020 (July 24-August 9), although you can appeal the decision.
De 23 years and born in Kenya, Jebet had stood out especially in 2016 by taking the Olympic title in Rio de Janeiro and later getting a new world record in Paris (8:52:78), then pulverized by Kenyan Beatrice Chepkoech (8: 33.32) in July 2018.
In any case, don't lose your 2016 olympic title, since its positive came later, on December 1, 2017.