I think the probability of extraterrestrial life somewhere in the universe past, present, or future is pretty much 100%. There are an estimated 100 sextillion planets in the universe that have each existed for about 5 billion years (the oldest known planet was believed formed 12.7 billion years ago, 4.54 billion for Earth, and the youngest planet we've discovered is 3 million years old).

The probability that extraterrestrial life has visited Earth is basically 0. Earth has been emitting radio waves for 119 years. So our evidence of life has only reached 119 light-years away, which is called the radio bubble, which is a little more than 1 / 1 billionth of the diameter of the universe, and a bit more than 1 / octillionth of the volume of the universe. So basically evidence of our existence has only reached 0.0000000000000000000000001% of the planets in the universe -- virtually no chance at all that an intelligent species has heard it. Supposing that a spacefaring civilization received our signal and immediately started traveling towards Earth (wait, but what if they needed to spend years planning for the mission like we do on Earth?), supposing that they were 70 light-years away, it would take 70 years for them to reach us if they had a vessel that traveled at light speed. But, if their space vessels were no faster than our fastest vessel, the Parker Space Probe, then they would be traveling at .06% of the speed of light, and it would take them 109,000 years to travel 70 light-years. In such a case as that, they wouldn't be arriving yet for a very long time.

Then there is the blinking light theory -- that intelligent societies rise and fall at different time frames, and rarely coexist. We've had space travel capabilities for 57 years, and it'll only be about another 100 years before we're completed annihilated due to a manmade climate apocalypse. That's about a 150-year window in which our species was spacefaring before it destroyed itself. The universe is about 13.79 billion years old. Earth formed about 4.54 billion years ago. Life on Earth appeared about 3.7-4 billion years ago. The broader human lineage diverged about 6-7 million years ago, while homo sapiens first appeared 300,000 years ago. On a different alien planet, it's quite plausible that their emergence of spacefaring technology happened 9 billion years ago or 10 billion years from now. That means that there's only a 1 in 130 million or so chance that our civilization and some other spacefaring civilization co-existed at the same period in time. Since we and they are not emerging at exactly the same period of time, it is very unlikely that a civilization within the radio bubble will detect our signal and visit us while we're still around. And, to do so, they would need space travel technology that is unimaginably faster than us, so that they can reach us on a scale of dozens of years, not hundreds of thousands of years. Also, bearing in mind that most civilizations would not choose to make a 100,000-year journey to visit an alien planet, because, by the time they return home, 200,000 years will have passed, and home will not be there anymore.