Conspicuous by your absence
Definition 1 of 1
Pro Tip 1/3Expectation at Events
The phrase is often used when someone's presence is expected at an event but they do not show up. 
At the family reunion, Uncle John was conspicuous by his absence.
Pro Tip 2/3Group Dynamics
Use it to highlight how a person's absence affects a group situation or dynamic. 
In the debate team's practice session, Maria was conspicuous by her absence.
Pro Tip 3/3Implicit Criticism
The phrase can imply a mild criticism or disappointment over someone not being where they're expected. 
When the awards were given, the main sponsor was conspicuous by their absence.