The GRAVITY instrument on the European Southern Observatory's Very Large Telescope Interferometer (VLTI) has brought significant advancements to infrared interferometry with its high spatial resolution and sensitivity. The ongoing GRAVITY+ project will equip the VLTI with wide-angle phase reference delay lines, state-of-the-art adaptive optics, improved vibration control, and other upgrades. These enhancements will not only greatly improve GRAVITY's performance but also reshape the entire VLTI system. In this talk, I will provide an overview of GRAVITY's technology and scientific achievements, highlight the recent progress of GRAVITY+, and discuss future opportunities for extragalactic supermassive black hole (SMBH) studies. GRAVITY+ will enable accurate measurements of SMBH masses and broad-line region structures for a large sample of AGNs at both low and high redshifts. Additionally, multiwavelength synergetic observations will provide critical data for investigating SMBH accretion, AGN feedback, and the search for SMBH binaries. I will conclude by discussing the prospects for the next-generation VLTI.
