The TVTropes Trope Finder is where you can come to ask questions like "Do we have this one?" and "What's the trope about...?" Trying to rediscover a long lost show or other medium but need a little help? Head to Media Finder and try your luck there. Want to propose a new trope? You should be over at the Trope Launch Pad.
Elephant in the Living Room if the event is obviously and currently impacting them yet they refuse to talk about it.
It kind of seems like a lot of assumptions otherwise. Most shows are Like Reality, Unless Noted, and "there is no evidence of any war ongoing in this show's world" would seem to fall into the "unless noted" bit.
It's far more notable that the real-life event does impact the story, which is Real Life Writes the Plot. The COVID-19 Pandemic is a particularly major example — see that page for all the media that incorporated COVID-19 in their stories.
But how do you (and why should you) list all the media that ignored COVID-19 and didn't incorporate it into their stories?
Edited by KD

Is there a trope for when characters don't acknowledge a (usually recent) major world event even when it feels like it would be relevant to do so. Not a case of Distanced from Current Events where something is altered to avoid causing offence, sometimes late in production. I'm thinking more like Brief Encounter where no one brings up the war despite the fact that it was still ongoing at the time the film was produced and the characters appear to be living in what was the present-day with no timestamps or suggestions of alternate timelines.