The problem of the universality of Quantum Mechanics has been debated for a long time, with some physicists in favour of it and others instead who consider Classical Physics to be more fundamental, to the extent that it is not necessary to quantise all physical systems. One of the most challenging topics emerging from this debate in contemporary physics is Quantum Gravity, whose goal is to unify the most fundamental theories known so far: General Relativity and Quantum Physics. Recently, promising laboratory-scale tests of quantum gravity effects have been proposed. They are based on the so-called “Bose-Marletto-Vedral effect”, which exploits entanglement generation between two masses interacting only with a gravitational field and acting as a generalised Bell’s theorem for models of matter-gravity coupling.