When Spartacus died during the final battle in the final episode then what happened to the gladiators who were left? Did they continue the fight or did they just run?
There is no explanation as to what happened to all of the rebel slaves. Of course Gannicus was crucified. The finale does show Nasir, Argon and other rebels remembering Spartacus. That scene is really the only explanation of what happens to the rebels after Spartacus death...which really is not an explanation, it just shows them alive after Spartacus death.
If you are curious as to the fate of Spartacus army from a historical view, well they were hunted down and killed or enslaved by Crassus.
They ended the scene like that because in Rome, slavery existed for more than a century. Only a very small amount of people rebelled and they got crucified later.
In order to show somewhat happy ending they showed like Spartacus saved some people and freed from slavery and then he died but he also one among the many rebel who fought for slavery.