Mitch McConnell has announced that he is stepping down as the Republican leader in the Senate:

https://www.theguardian.com/us-news/2024/feb/28/mitch-mcconnell-step-down-republican-leader-senate

The Guardian have named John Cornyn, John Barasso and John Thune among his most likely successors and they are among the early favourites on the Manifold market - 

Will his successor be one of these three or another John?

The market resolves to YES if their first or their surname is John. Middle names don’t count unless they go by their middle name as their main given name.