Should wildlife hunting be banned?
Millions of people were outraged but back in the African country of Zimbabwe, where Cecil lived, it's sparked a debate about how much protection wild animals need.
Brent Stapelkamp, the Zimbabwean researcher who followed Cecil the lion for nine years, and was the one who discovered he had been killed, says he opposes a ban on hunting.
Many people say the money raised by hunters helps keep the wildlife parks in business.
Watch Leah's report.