I want to display entries that have a field that is the same as a field in a global variable
Since you've confirmed that the issue is in the if statement and I can see your comparison, I'll clarify usage and propose a solution.

The in operator, is a containment operator and it expects a scalar|primitive value on the left and an array|iterable on the right.

I am assuming that entry.publishYear is an int or a string: 2017. However, I'm not sure about currentEdition.currentYear. It seems like it's also an int or string: 2017.

If the currentEdition.currentYear is not an array or an iterable item, you should use == instead of in.

{% if entry.publishYear == currentEdition.currentYear %}

Have you tried that? Or can you try it and let me know?