Will and Robot (the latter being the original robot he first befriended back at the series’ start) have certainly been through a lot during the series’ limited run. Specifically, in the final season, Robot sacrifices himself to repair Will’s mechanical heart after it stops beating — and his sacrifice inspires his ally robots to join the side of the humans in the coming battle. Later, Will is stabbed in the heart by the leader of the evil robots, and the piece of Robot living inside Will leaps out and takes control of the other robot’s body, essentially being revived in his efforts to protect Will one last time.
In the epilogue, we see Will and Robot set off into space to explore another planet, providing the perfect setup for a spinoff where the duo might visit various new worlds in their journey across the stars. Perhaps the series could delve deeper into the mysterious creator of Robot, or perhaps the two could scout new worlds thought to be hospitable for humans.
While this is nothing but speculation, the premise certainly seems right in line with Will’s character. Considering how crucial the dynamic between the boy and his robot is to the show, it wouldn’t be so hard to believe that bond would translate into another series.