If you want to start search library databases for content regarding Black/African American communities, you can use the following terms to get started on your search:
The PubMed standardized medical subject heading (MeSH) term for Black/African Americans is "Black or African American"[Mesh]; this should be used for population groups in the US. Other terms that you can use include African American, Afro American, and Black American. You could also use "Black People"[Mesh] which would cover anyone who has origins in any of the black racial groups in Africa – this would be helpful if you are considering population groups outside the US.
Please note: “Race and ethnicity terms, as used in the federal government, are self-identified social construct and may include terms outdated and offensive in MeSH to assist users who are interested in retrieving comprehensive search results for studies such as in longitudinal studies.” - PubMed
An example search string that you could use could be: ("Black or African American"[Mesh]) AND asthma
In CINAHL, you can try (MH "African Americans") or (MH "Black Persons+"). The Black Persons term includes results that relate to African Americans, Black Africans, Black Brazilians, Black British Persons, Black Canadians, Black Caribbean Person, Black LGBTQ+ Person, and Black South Africans. You can always adjust what’s included in the term list in the CINAHL Subject Headings section.
An example search string that you could use could be: ((MH "African Americans") or (MH "Black Persons+")) AND heart disease