Source:

https://www.ajc.com/news/nation-world/western-troops-on-the-ground-in-ukraine-is-not-ruled-out-in-the-future-french-leader-says/LDTMYLAUOZETBBIIP6TJKTCQ7Y/

Resolves YES if any NATO nation (excluding Ukraine, should it be added to NATO) sends official NATO troops OR its own militia to fight in Ukraine. Non-combat support or weapons do not count.

EDIT: question concerns deployments in 2024, but resolves 2025 so that info can come to light in case of major but covert deployment