Well, that’s what some out-there thinkers have thought up.
The issue which they are drawing on is the uniformity of the Universe’s temperature. At present, the big bang theory says that the temperature is uniform throughout because of ‘inflation’, a time when the Universe expanded faster than the speed of light.
This model, that we exist within the 3-dimensional event horizon of a 4D black hole, apparently explains the uniform temperature.
Of course, it doesn’t explain what caused the Universe which housed the 4D blackhole… and really places us into the similar problem of regression presented by the big bang theory, plus such a theory is not verifiable and is thus (arguably) more conjecture than good science.
Here is the link, Did a hyper-black hole spawn the Universe?
Also, here is an hour-long guide to black holes.