High performance networking on the whole, of which HPC GPU solutions are only one use case. And there's the continuing trend of sticking offload engines in the form of ARM ASICs alongside devices that connect over PCIe.

A bit farther into the future: https://genzconsortium.org The idea of everything being connected by a shared high speed fabric enables ideas like shared memory pools across a fabric for 'composable' configurations. https://drivescale.com/software-composable-infrastructure/