If nullable in a if statement [duplicate]

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• What do two question marks together mean in C#? 14 answers

Can some one explain what does this piece of code is doing.

bool? Following;

If (Following ?? false)
    // do something. 

My first though is that it means, do something if "Following" is true or false. If so, why not just check if not Null or has value? And that is why I'm confused.

EDIT: I know what the ?? Means. I just never saw it in a if statement.