If you don't know who Cardi B is, you'd better catch up quick. The rapper's hit single "Bodak Yellow" recently peaked at number one on the Billboard Hot 100 chart — and made history. Cardi B is the first female hip-hop artist to top the chart since 1998. There have only been four other female rappers to do so. Women in hip-hop have a strong legacy, but why has their success in popular music been limited of late?