On the surface, it's different. Running in situ means drawing a circle around your station in a small space, any venue, while people stand in the circle, running like standing still, pushing their legs up, so that the whole body is in a state similar to running. Running mostly refers to outdoor running. There are many places, and it is also a real running action, not just a running state like in situ.
From the effect of reducing fat, running in situ is definitely effective, and its fat burning degree is higher than brisk walking and lower than jogging. Running in situ is not as good as running outdoors. It's easier to run in place.