Gates, Arden, Mueller top FORTUNE's list of "World's Greatest Leaders"

1. Bill and Melinda Gates ("Transforming Life for Billions")

2. New Zealand Prime Minister Jacinda Ardern

3. Special counsel Robert Mueller

4. Tencent founder and CEO Pony Ma

5. Microsoft CEO Satya Nadella

6. Greta Thunberg, Swedish student and climate activist

7. Margrethe Vestager, European Union competition commissioner

9. José Andrés, chef and CEO, World Central Kitchen

10. Walmart CEO Doug McMillon and Lisa Woods, Walmart senior director specializing in healthcare design

14. Apple CEO Tim Cook

18. The Pink Wave: 42 newly elected women in Congress

Explore the list.