What does the title of the article, the hansberry of chicago: they join business
acumen with social vision mean?

Strictly speaking, to have "business acumen" is to have the competency to make a sound judgement or a correct decision in a matter related to business, although, more generally speaking, it could also apply to other subjects. Furthermore, to have "acumen" is to have the keenness, the quickness, and the depth of discernment to understand and deal, practically and successfully, with a situation. Finally, to have social vision can be understood as a way of thinking or acting that seeks, or at least takes into account, the welfare of other fellow citizens, particularly if they are disadvantaged.

Carl and Nannie Hansberry were part of Chicago's prominent business class, and, although they never forgot their humble origins, they decided to move to an affluent area of the city that was restricted to white people. They suffered the threats of their neighbors, but continued to live there, and they even defended their case in court, setting an example of the African Americans' fight for their social rights.

The title of the article, therefore, could suggest that the Hansberrys sought to have a better life and they asserted their right to pursue that goal, using good judgement when faced with the incomprehension of their white neighbors, and speaking on behalf of other African Americans who were also advocating for their social rights.