The great scientist Albert Einstein mentioned this in a paper (Photoelectric Effect) in 1905 and explained the importance of discovering it.
After that, many scientists joined this fact. The gravitational waves created by the collision of black holes confirm that the graviton might exist, which is why many scientists are engaged in its search.
Just as the Higgs boson is responsible for the creation of the Higgs field, similarly, the graviton is directly responsible for the gravitational field.
However, the Higgs boson, a fundamental particle, provides mass to other particles through its Higgs field. Therefore, the Higgs boson was clearly identified in the Big Bang experiment.
But the graviton does not work this way. It reacts with the mass of two particles and behaves differently and invisibly with one particle.
This is why an astronaut feels weightless while floating in space. This is also the reason why we cannot directly identify the graviton.
For this, we will have to use the most advanced technology. We will also need to examine the gravitational field.
If we have such advanced technology that can investigate the beginning and end of the gravitational field between two particles, then we can identify the graviton.
Since the graviton reacts between two particles, we will have to search for it in two particles. This seems unimaginable, but it is also true that we cannot search for the graviton in a fundamental particle.