These are only the leaders and obviously over time the membership of the Congressional Black Caucus changed with the different elections. Someone else may add the data.
The information I used could be found on English Wikipedia and is part of the article about the Congressional Black Caucus. Typically, when a position is considered important enough, it has its own article. When it does, it has more relevance and more information is available about the relevance and the history of such a position.
When Black representation matters, you want substantial lists and articles both on Wikidata and Wikipedia.