What that means is that gravity, at the quantum level, must be conveyed by a spin-2 particle, known as a ‘graviton’. It has not been detected, and probably never will be (due to technical limitations). We can broadly pin down its properties, but we do not yet have a full theory of how it interacts.
The existence of a solution to abstract equations that involve gravitons does not imply the existence of gravitons. Designing an experiment to measure and confirm the existence of the particle is a different endeavor.
What was discovered is the existence of gravitation waves, long wavelength limit to the weak quantum gravity (aka propagating and interacting gravitons)
So, has this been discovered recently? I was under the impression that the graviton was theoretical?