KFOR, the NATO peacekeeping force in Kosovo, has gotten a larger troop deployment in the last week [0].
Serbian soldiers crossing into Kosovo is a clear violation of the Kumanova Agreement AND unlike Russia-Ukraine they will be de facto declaring war against the US and NATO due to the American and EU boots on the ground, and bye bye 25 years of work to try and join the EU.
It's just election posturing by Serbia, as Vucic promised calling a snap election in the coming weeks in the aftermath of a mass shooting in May 2023 [1] destroying his popularity and sparking mass protests reminiscent of Euromaidan and Gezi Park.
[0] - https://www.politico.eu/article/nato-builds-up-forces-kosovo...
[1] - https://www.politico.eu/article/serbia-snap-election-2023-al...