We’ve listened for radio signals for decades. A recent study even looked for the waste heat from galactic civilizations. So far we’ve found nothing that didn’t seem natural. Maybe that’s because;
“Any sufficiently advanced technology is indistinguishable from nature.”
The search continues, especially because we’re realizing habitable worlds are more plentiful than originally thought, and life can handle more extreme environments than we originally thought. The diversity in alien civilizations is probably near infinite. Even if the vast majority are stealthy or transmitting in ways we can’t imagine or detect, somewhere out there is at least a minority doing something similar to us. In the meantime, we just have to keep banging the rocks together and listening for the echoes.