How could I start an argumentative essay about how racism still exists?

Evidence for the continued existence of racism can be found on a number of different levels. Examining racial differences in incarceration rates and rates of police brutality, contemporary racial hate groups, and representation in American media might be a good starting point for finding a variety of different types of racism.

Some evidence for the continued existence of racism can be found in Michelle Alexander's book, The New Jim Crow. In this book, Alexander uses statistics to prove that African Americans are incarcerated for drug crimes at much higher rates than  white Americans, despite the fact that white Americans are more likely to commit drug crimes. Alexander argues that differing incarceration rates have developed a "racial caste system" to deny opportunity to African Americans. African Americans are additionally more likely to be assaulted and even killed by police officers than non-black Americans.

Other evidence for the existence of racism includes the continued existence of hate groups such as the KKK, and the lack of representation of nonwhite people in American media. According to UCLA's 2015 Hollywood Diversity Report, people of color are greatly underrepresented in all media jobs; although minorities constitute 40% of the U.S. population, white lead actors in broadcast TV shows number nonwhite leads by a ratio of six to one.