This is a great question. Progressives did a lot to help immigrants and blacks in culture. Let me name a few ways. First and most importantly, they had a heart to help and do something. This point cannot be emphasized enough, because doing something is the first step.
Second, they educated people on social problems and ways in which we can move forward. For example, in most universities now, there are whole majors that can be done on topics that deal with blacks and minorities. This did not exist in the past. Third, many progressives created organizations to help blacks and immigrants. Some of the organizations helped with social welfare and other helped in other important areas such as the law.
Third, at times progressive demonstrated as they took to the streets for change.
Finally, progressives also worked to get laws changed, like immigration laws, which allowed many people to come to America in the 1970s.