The recent years have seen the increasing power of Gaia's astrometry for characterizing candidate exoplanets detected by radial velocities and high-contrast imaging, and even identify new candidate planetary system. By combining these methods with the astrometric data reductions published in the Gaia archives, it is permitted to fully determine the orbital inclination, true mass and thus assess the planetary nature of candidate companions. But Gaia also makes it possible, via the two accelerated motion indicators that are astrometric dispersion (RUWE) and proper motion anomaly, to predict the existence of companions, including hitherto unknown exoplanets, beyond the ice line. I will review the current capabilities of Gaia to characterise systems with long-period substellar companions, and present many new exoplanet candidates unearthed from the third data release of Gaia.