We've already found extra-terrestrial life in the form of extinct fossilised Martian bacteria. So I think it's certainly possible that extant complex and possibly even sentient and sapient extra terrestrial life could exist.

But this leads to another question, are alien visitations (e.g. extra terrestrial UFOs, covert abductions etc.) real? Because to travel from just the next galaxy to ours would consume an incredible amount of resources, regardless of how advanced a civilisation may be. Which means that they wouldn't come all the way here and not make themselves announced. It'd be like if a person flew to another country, secretly took photos of the locals, maybe abducted a few for experimentations, then flew back. That's a lot of effort to do something so covert. Also, they would most likely only justify the voyage here if they felt that they had something to gain from Earth (e.g. resources). So there's a fair chance that if a more advanced civilisation came here, they may want to conquer, exploit or eradicate us in order to get at whatever resources we have that they need. Even if they just came here to colonise and make a new home, we'd most likely be screwed, because look at the entire history of whenever one civilisation colonises somewhere else and what happens to the indigenous population. It's never a good outcome for the locals.

If the aliens are so advanced that expending such resources to travel across the galaxy is negligible, then there's a chance that we would be so 'primitive' that it wouldn't even be worth their time/effort to visit us. We'd be like a sentient species of insects to them. They'd either just leave us alone or destroy us (latter might happen if we had a resource that they needed). If humans found a colony of insects sitting atop a gold mine, do you think that we would kindly relocate those insects before mining that gold? There are already many species of Australian mammals and reptiles that are currently endangered due to mining.

Or maybe the problem with these hypotheses is that they're applying human standards onto extra-terrestrials. Perhaps they are better than us and would simply wish to make first contact and invite us to be their friends.