In Shakespeare's play, Julius Caesar, Cassius does not ask Antony or Octavius to kill him.
In Act Five, scene three, Cassius asks for a report as to how his army is doing. He asks Titinius to ride his horse afield and return to report the progress of Cassius' army and the enemy. Pindarus reports that Titinius has been taken by the enemy. Cassius laments having lived so long to see his best friend taken by the enemy. Cassius reminds Pindarus that in saving his life, Pindarus owes his allegiance to Cassius; he must do whatever Cassius asks of him.
And so, he takes out the sword he used to kill Caesar and demands that Pindarus keep his promise. Cassius grants Pindarus his freedom; then Cassius says that he will cover his face, and when this is done, Pindarus must stab and kill Cassius, which Pindarus does.
When Cassius believes he has lost the war, when he sees his best friend taken by the enemy, he asks to be put to death with the same weapon used on Julius Caesar, declaring as he dies:
Caesar, thou art revenged,
Even with the sword that kill'd thee. (lines 47-48)
Antony and Octavius have nothing to do with Cassius' death.