2020 Republican female/minority candidates

[fredtoast]

The Democrats' best candidate for 2020 Presidential election may be a white guy who is not young, but I believe they will have multiple women and minority candidates. Republicans will probably do like every party does when they have the incumbent and get behind Trump. But it seems like the most likely opposition, even from within the Republican party, would be a female or minority candidate who feel disrespected by Trump.

So who might be that female and/or minority challengers for the Republican ticket in 2020?

No one still takes Palin seriously do they?

What about Ben Carson or the pizza guy?