An exciting discovery made by space- and ground-based high-energy missions is the detection of gamma-rays from over 3000 active galactic nuclei (AGN). Despite the intensive study of AGN, the location and origin of gamma-rays remains a mystery. A feature common to all high-energy emission models is that the gamma-rays are expected to be associated with the compact regions of jets energized by the central black hole. The exact location of the gamma-ray emission region is still unknown. Some studies suggest the emission region is located close to the black hole; while there are counterexamples which argue gamma-rays coming from father out in the jet. High angular resolution observations offer an unparalleled opportunity to probe and pinpoint the high-energy emission. High-energy (MeV) polarization observations by the future missions (e.g. All-sky Medium Energy Gamma-ray Observatory, AMEGO) will shed more light on the energetic particle-acceleration processes and emission mechanisms in these enigmatic objects. I will present the high-resolution polarization study of gamma-ray bright blazars and the high-energy polarization detection capabilities of AMEGO.