Ill take a stab at this. If theres an alien race that has done light speed travel of course they know we are here. We are the "Black Sheep" of the universe if "Everyone" else is traveling in space for lunch and were stuck here sending a few people up in a giant plane and back and thats the most and farthest weve gotten. Ive seen video's on netflix saying that UFO's have been here forever, and what not, my question is if they have been here and few have seen them they arent hiding for no reason.
That there are, on some other planets somewhere in the vast universe, some forms of sentient life is almost inevitable. Assuming such creatures do exist, it's almost certain that they're not aware of us as they would be subject to the same limitations presented by the sheer scale and scope of the universe and the miniscule impact upon it life on any one planet could realistically have. It's always possible some alien species has the ability (and desire) to identify us but I see no reason to believe that has actually happened.