Measurements of the anomalous magnetic moments have been a crucial check of the higher order theory calculations for about a century. The best result for the muon was obtained by the Brookhaven E821 experiment at the start of this millennium and it showed a discrepancy from the Standard Model prediction by more than 3 standard deviation. The muon g-2 experiment at Fermilab represents a significant improvement both in the beam and in the detector. The results obtained with the first data collected in 2018 will be shown and compared to updated theory predictions.