Black Lives Matter (BLM) is a decentralized political and social movement that aims to highlight racism, discrimination, and racial inequality experienced by black people and to promote anti-racism. Its primary concerns are police brutality and racially motivated violence against black people. The movement began in response to the killings of Trayvon Martin, Michael Brown, Eric Garner, and Rekia Boyd, among others. BLM and its related organizations typically advocate for various policy changes related to black liberation and criminal justice reform.
https://en.wikipedia.org/wiki/Black_Lives_Matter