Through advanced experimental techniques on CrI$_{3}$ single crystals, we derive a previously not discussed pressure-temperature phase diagram. We find that $T_{c}$ increases to $sim$ 66,K with pressure up to $sim$ 3,GPa followed by a decrease to $sim$ 10,K at 21.2,GPa. The experimental results are reproduced by theoretical calculations based on density functional theory where electron-electron interactions are treated by a static on-site Hubbard U on Cr 3$d$ orbitals. The origin of the pressure induced reduction of the ordering temperature is associated with a decrease of the calculated bond angle, from 95$^{circ}$ at ambient pressure to $sim$ 85$^{circ}$ at 25,GPa. Above 22,GPa, the magnetically ordered state is essentially quenched, possibly driving the system to a Kitaev spin-liquid state at low temperature, thereby opening up the possibility of further exploration of long-range quantum entanglement between spins. The pressure-induced semiconductor-to-metal phase transition was revealed by high-pressure resistivity that is accompanied by a transition from a robust ferromagnetic state to gradually more dominating anti-ferromagnetic interactions and was consistent with theoretical modeling.
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