First evidence:
In a dialog between Gohan and Piccolo, Piccolo says that knowing Goku's personality, he will fight the mysterious opponent in the first match using all his power.
Second evidence:
Anyone who has the game could send me images from the game's encyclopedia about the new DLC: Story (including notes) and characters (only Goku, Uub, Vegeta, Goten, Trunks, Pan and Piccolo).
In the manga, number 16 states that Cell's goal is not to assassinate Goku, but to cause the destruction of the entire universe.
But the context of this statement could be referring to the destruction of the universe over time.Cellular has a set of Saiyan and Namekian cells, with two species...
Daizenshuu TV Animation Parte 3 e Chozenshuu 3
*Buu sticks his head out of the wall of flesh. Moreover, inside his body, Buu is immortal. On the other hand, Goku's power is less than 1/100 of its original power.*