I think Marco and the samurai will protect the strawhats at the end of Wano when they are unconscious from all the fighting from the Cp0 as they come to clean up the battlefield. Maybe he'll strike a deal with them and let them capture Kaido and his crew and let Lffy and the rest go.
I’m pretty sure Marco by the end of the arc will tag along Sunny-go “temporarily” where the SHs will drop him on WB territory... maybe the anime also give a filler arc between them like Bartolomeo for example between Dressrosa and Zou
Because I truly think it will be the best way for Oda to make the SHs and Luffy specifically pay a visit to Ace and WB grave to pay respect...
Especially after honoring Ace’s goal of taking down Kaido and restoring peace to Wano and for Otama...
For me, I play this scene again and again in my head and always get emotional... I hope Oda at least has some similar thoughts...