The killing failed to restore the Republic. Instead it led to Caesar's deification and a civil war between his supporters and his killers, which became a stage in the Republic's collapse.
Based on Wikipedia: Assassination of Julius Caesar
The assassination failed to achieve its immediate objective of restoring the Republic's institutions.
Instead, it precipitated Caesar's posthumous deification and was followed by the Liberators' civil war (43–42 BC) between his supporters and the conspirators, which became a stage in the collapse of the Republic.