As wikipedia puts it: "The assassination failed to achieve its immediate objective of restoring the Republic's institutions. Instead, it precipitated Caesar's posthumous deification, triggered the Liberators' civil war (43–42 BC) between his supporters and the conspirators, and contributed to the collapse of the Republic. These events ultimately culminated in the rise of the Roman Empire under Augustus, marking the beginning of the Principate era."

If that day says anything about the end of tyrants, it's that murdering one can sometimes be futile and counterproductive.