I want to caution everyone here against assuming that because Alsobrooks is black and the majority of Maryland's Dem primary voters are black, that she will win the primary over her white male opponent, Trone.
The last open seat Senate election here back in 2016 also featured a well-known black woman running against a white male Congressman. The latter ended up winning and then winning re-election last year.
Van Hollen won in large part because his Congressional office had a reputation for being more responsive to constituent assistance requests than Edwards'. That, and the fact that Edwards was (and is, to my knowledge) aligned with the Sanders wing of the party, which is not especially powerful in Maryland.
Alsobrooks does not have either of these problems against Trone, and certain negative things about Trone's reputation, both real and imagined, have preceded him in Maryland politics since even before he was elected.