According to Wikipedia, U2's '360 Degrees tour' was surpassed in actual gross by Ed Sheeran's '÷' ('divide') tour of 2017–19.
U2's tour is still the highest–grossing after adjustment for inflation, and it must be said that there was more than enough information in the question to enable the informed contestant to give the right answer. Hence this is only a comment, and not a black mark for the answer being wrong!
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