The answer of Cambridge International is :
“If bias or discrimination affected your predicted grade(s) or rank order position(s) for the June 2020 series, this could be a form of malpractice. If you think malpractice has affected you, then in the first instance you should discuss this directly with your school or college, and raise a complaint through its complaints policy.
If you feel your school has not addressed your concerns, you could then consider raising your concerns about malpractice with us. You can contact us here. This would not be an appeal, but an allegation that malpractice occurred in relation to your centre assessment grade(s) or rank order position(s). Such allegations would be serious, and taken seriously.”
To elaborate more, this is not appeal, in other words, your grades will not change but Cambridge will not tolerate any malpractice by any school and the school might be penalized.