For real though, I REALLY doubt Marco will participate in the fight against BM since, like Luffy vs Kaido, its supposed tp be a new gen vs Old gen thing, its way more likely that he went to the basement where Yamato is since him and Izo were going after the Kazenbo before....and I hate that because if he helps Yamato against a fucking drawing I wont hear the end of it
My biggest hope is that he will actually go after Zoro and help against the effects of the mink drug