The proliferation of 400Gb/s Ethernet (400GbE) in our computing and networking infrastructure is stimulating rapid transformations in our wireline links. A wide array of new technologies are under research to support next-generation 800GbE in the areas of optics, packaging, modulation, coding, and transceiver architectures and circuits. Over the past two decades, progress on wireline interface bandwidth scaling has followed a relatively clear path. But, for many, the coming years seem less certain. In this forum, eight experts illuminate the future, sharing their diverse expertise across the broad range of topics that promise to have impact on optical and electrical transceiver R&D in the 2020’s.