There is potentially other life that exists in the universe, or our galaxy, maybe still even in our solar system.
The problem is the vast distance. The recent planet they believe has indicators of biological signatures in its atmosphere is 125 light years away. That means that a signal sent today would take 250 years before we get a reply - if there is intellligent life on that planet that is capable of sending radio signals.
Just for context, travelling at 400 000km/h, it would take almost 200 000 years to reach that planet. Broadly speaking , this is a close planet when you consider the milky way is 100 000 light years across.
For arguments sake, if there is a civilisation exactly like us, with all the exact same technology etc, that has evolved somewhere else in our galaxy, chances are we will never know about it.
However, using the same argument, lets say that the civilisation like ours is 1000 years more advanced than us? If humans dont self-destruct, what technology will we have in 1000 years? Will it be possible to crack all the problems involving space travel distances in that time? What if the civilisation is 10 000 years more advanced? 10 000 years is the blink of an eye in evolution and maybe humans could make breakthroughs in science that seem impossible today, once again - if we dont annihilate ourselves in the meantime.
If life is common in the universe and if there are civilisations that have developed like ours and are thousands of years ahead of us, then there is a chance that aliens are here already.