No alien life will ever exist in the universe
Not only does life currently not exist elsewhere in the Universe, it has never existed and will likely never exist in the obervable universe
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The Argument
All arguments that apply to the idea of no simple life forming outside of earth apply to this, amongst other cases detailed below:
1) The Fermi Paradox:
This is a logical argument that is often used to support the idea that intelligent civilisations are likely extremely rare in the universe. The paradox goes as follows:
There are over 100 trillion stars in the known universe, many of which are older than our Sun, and around at least some of these stars there will be planets that are Earthlike, and hence have a probability of developing an intelligent civilisation. And of these, a fraction will develop interstellar travel.
Using simple modelling it has been shown, even for a relatively slow interstellar civilisation, the MilkyWay could be conquered on the scale of tens of millions of years. A tiny fraction of how long the Universe has existed for.
From Earth, we see absolutely no evidence of any interstellar civilisations, such as Dyson swarms or any form of communication between stars in any of the millions of galaxies we've observed. The fact we see none is a strong case against the existence of intelligent life.
2) The Drake Equation
Similarly to how the Drake Equation(See argument for there being intelligent life in the Universe) can be used to argue for the universality of intelligent life, it can just as easily do the opposite due to its highly speculative nature.
Using far more conservative numbers for the calculation we obtain a value for the number of intelligent civilisations in our Universe as being 9.1E-11 or 0.000000000091 per Universe. So if we are already here, the chance of there being another is closer to 9.1E-22( 9.1 with 22 zeros' beforehand).
Counter arguments
Counter to the Fermi Paradox:
The most commonly used solution to the Fermi Paradox is termed the "Rare Earth" hypothesis which disputes the idea that Solar Systems that contain Earth-like planets and conditions are common.
It instead proposes that there is something special about either our location in the quiet galactic arm or possibly something else such as specific concentrations of certain chemicals and molecules that has allowed Earth to form simply making life rarer than we expected, but not non-existent
Counter to the Drake Equation:
Almost all of the terms within the Drake Equation are either rapidly evolving or simply unknown values that lots of groups speculate to be different values.
Using the figures that you estimate to be correct you can obtain almost any value within the Drake Equation to fit your agenda
Premises
There are billions of opportunities for intelligent life to arise, and more than enough time has occured to galaxies to be conqured hundreds of times over, yet we see absolutely no evidence of this in any of the billions of galaxies we have observed.
The Drake Equation, when input with more conservative values gives extremely low odds(essentially 0) of there being another intelligent civilisation alive in the universe.
Rejecting the premises
Like much in this topic, the assumption that there have been billions of chances for intelligent life to arise is purely speculation. The rare earth hypothesis states that there may, in fact, be something special/rare about our location in the Universe that we don't yet know about that has allowed life to evolve.
The Drake Equation can be used to give essentially any value you want depending on what you estimate the input values to be as almost all of them are at best, very rough estimations.