Even if we detected 100% certain alien life, not much would change imo. Normies would just go "Huh, neat! Anyway, can you believe what Kayne said", and governments would just assess it as a threat and keep telescopes pointed that way to see what they could learn

Even when the UFO disclosure was going on over the last few years, with the Pentagon itself outright saying "There are unknown objects stalking out naval ships and flying past our military bases" nobody cared. If you even try to talk to people about it, it's just "Huh that's weird, probably the Chinese / Russians" as if that also isn't a very scary thing

IMO the US government could outright say "Aliens are living on Mars and we've contacted them" and people would still not really care and would just go on with their lives and go back to work etc.