In answering the question of what contributions Malcolm X made to society, we first must ask, what society? Malcolm X, who died on the cusp of landmark civil rights legislation, lived his life in an American society that was split into two clear parts by segregation. Wholly by white design and wholly to serve white interests and prejudices, there were two worlds within one country, one Black, one white. The dominant white society oppressed and exploited Black people within its borders, using its labor but forcing it to live apart and in poverty.
Malcolm X unquestionably contributed enormously to Black society, instilling it with pride in its Black heritage and offering it a vision going forward of building a robust culture and economy by turning its back on whites. He provided a compelling alternative narrative to Martin Luther King's dream of an integrated society based on non-violent resistance to white supremacy. Malcolm forcefully articulated Black doubts that such an assimilationist vision could succeed against white violence, hatred, and treachery. He built a strong platform for Black self sufficiency and autonomy, modeled Black self education and self discipline, and fearlessly justified the need for Black people to be armed and powerful. This was unquestionably threatening to white society.
Malcolm's contribution to white society is more problematic and made even more contradictory by his late life changes in attitude towards whites. Through most of his life, he held up a mirror of white violence against Black people by wholly adopting the white ethic of justifying physical force against a feared "other." He faced white people with an organized group willing to use violent tactics against white people just as they had used against Black people. He made a compelling case that the only language whites understood was the language of violence and pain. In so doing, he arguably pushed whites into the arms of King, which led to a much overdo and needed and beneficial attempt at integration and redressing wrongs.
However, Malcolm's transformative experience on pilgrimage to Mecca, where for the first time he was treated as an equal to whites, opened up the possibility that he would have been willing, had he not been killed, to be creative in engaging in beneficial forms of collaboration with white culture.