My existing and new projects
I tested the operation in each new scene.
In my new project, I verified that the camera worked well in both the demo scene and the scenes I created.
However, in an existing project where I actually want to apply it,
Scripts such as demo scenes and new scenes don't seem to work at all.
In a new project, a warning message will appear if you do not add an event system to the scene.
In an existing project, even if you do not add an event system, there will be no warning message.
The script itself doesn't seem to be working... I don't know what the problem is.
Both Unity versions were tested with 2020.3.48f1.
What solution is there?