The race of the two professors, obviously.
Routine research often is easier to get through funding committees and get published. Less "what journal does this fit in, I'm not sure our division should fund this, does the PI truly have the expertise needed to do research in this, this result doesn't clearly advance the field"
Given that both were women, gender wasn't the deciding factor. And so race becomes the most likely desirable background to matter.
Some school systems are very explicit about this. See https://pacificlegal.org/california-globe-university-of-cali... for criticism of the UC schools on this. But as https://www.economist.com/united-states/2023/02/04/american-... makes clear, the trend is happening nationwide.