There was a shooting at a Trump rally. Details are still being released. The meme is referencing the successful assassination of Shinzo Abe a couple years ago.
And the part that is the most damning detail, it wasn't who the Republicans want it to be. The gunman was a registered Republican in Pennsylvania. Apparently the motivation was because Donald Trump disavowed Project2025.
From that he was a registered Republican, but also donated to a Democratic vote registering initiative. This would've been the first election he was old enough to vote in. No word of his actual motivations, but the idea that he's a fascist who didn't like that Trump wasn't fascist enough doesn't seem to bear out from this article at least.
Tbf, when one says "shooting" it conjures up images of an active shooter scenario. What happened was more aptly described as an assassination attempt. Target (trump) wounded (barely), one (or possibly two) bystanders dead, shooter dead.