How do you run CPU-bound work without blocking the UI?

Offload CPU-bound work with Task.Run so it executes on a thread-pool thread, await the result, then update UI on the main thread. Don't use Task.Run for I/O (await the async API directly). Keep the UI responsive by never blocking it with .Result or .Wait().

var result = await Task.Run(() => ExpensiveCompute(data));
resultLabel.Text = result.ToString();   // back on UI thread after await