In the Soviet Union in 1937, a worker of the People’s Commissariat for Internal Affairs finds a list of traitors, which he thinks is going to be his way out.

I like it. It feels like a good setup, but not much for. Everything in your logline can be done in just the first scene.

For instance, switch the USSR for Morocco, the "worker" for Peter Lorrie and the "list of traitors" for "letters of transit." We have an excellent setup for Casablanca, but it doesn't really touch what the story is really about.

I think what you've got here is a time period and a setup: In the Soviet Union of the 30s, a (describe your protagonist's flaw) government agent finds a list of traitors ...
But what you don't have, besides the vague "he thinks this is going to be his way out", is a goal. Now that he has the list, what's the plan? Does he want to expose it? Does he want to show it to his superiors to gain favour? Does he want to use it as leverage to blackmail them? Does he want to gain asylum with the Americans? Without the goal, the genre is unclear, as are the stakes.