In Act 5, Caesar alludes to his future murder, a real historical event that audience members would likely have been aware of. This creates a sense of dramatic irony and foreshadowing in the following passage, as the audience is privy to information that Caesar is not:
RUFIO: Caesar: I am loth to let you go to Rome without your shield. There are too many daggers there.
CAESAR: It matters not: I shall finish my life's work on my way back; and then I shall have lived long enough. Besides: I have always disliked the idea of dying: I had rather be killed. Farewell.
This passage also serves as an instance of foreshadowing, alluding to the abrupt, predetermined end to Caesar's life. Though Caesar is ostensibly unaware of his own death, one cannot help but feel in this scene that he has some knowledge of the role his murder plays in progressing the narrative of history. He asserts that he will finish his life's work on the way back to Rome, implying that his life's work is to go to his death. On a a similarly metatextual level, Rufio seems aware of the historical significance of Caesar's murder, referencing perfectly the method by which Caesar will soon be killed.
At the very end of Act 5, Apollodorus converses with Cleopatra as they watch Caesar depart for Rome. Apollodorus attempts to console Cleopatra about Caesar's departure in a moment of dramatic irony, foreshadowing future events that are fated to take place beyond the time frame of the play:
APOLLODORUS: [to Cleopatra] No tears, dearest Queen: they stab your servant to the heart. [Caesar] will return some day.
CLEOPATRA: I hope not. But I can't help crying, all the same.
As contemporaneous audiences would no doubt have known, Caesar did not ever return to Alexandria and will never see Cleopatra after the events of the play. In fact, he is stabbed in the back and dies in Rome not long after returning. Though Apollodorus makes this comment about stabbing to metaphorically explain his own emotional response to Cleopatra's sorrow, this comment is nonetheless followed by the statement, "[Caesar] will return some day." Taken together, these statements—along with Cleopatra's trite response of "I hope not" to the prospect of Caesar's return—foreshadow the Roman leader's tragic end. Neither Apollodorus nor Cleopatra are aware of the significance of their statements with regards to future events. Audience members who are familiar with history, however, will know where Caesar's story is headed and thus experience this final moment of Act 5 as dramatic irony.