CCM didn't do amazingly with Latinos when she ran in fact I think she underperformed Hillary with them. And I don't think she speaks Spanish so not sure she gives him the boost people think she would. Also as we saw in '16 black voters are a lot more impactful even beyond the South, look at PA, WI, MI... Ideally he picks a female black VP, problem is Harris will be amplifying an issue thats likely to dog Biden w/ black voters, criminal justice. We'll find out soon enough whether Abrams will be out of contention and running for Senate.
Cortez-Masto will make as much inroads with the Hispanic community in Nevada as Rafael "Ted" Cruz (who also does not speak fluent Spanish) made with the Texas Hispanic community.