Here's the primary source

https://iopscience.iop.org/article/10.3847/2041-8213/adc1c8

They possibly detected dimethyl sulfide, which is only known to be produced by living organisms.

Firstly that is completely badass science. The idea that you can use observations to detect the chemical composition of an exoplanet millions of kilometres away is an absolute triumph of the work of thousands of people over hundreds of years. Really amazing and deeply humbling to me.

Secondly, my prior was always that life existed outside of earth. It just seems so unlikely that we are somehow that special. If life developed here I always felt it overwhelmingly likely that it developed elsewhere too given how incredibly unfathomably vast the universe is.

Some speculation

On DMS:

- DMS is a very specific configuration that’s rarely the endpoint of non-living chemical cycles.

- The simplicity of DMS doesn’t make it less indicative of life—it actually makes it a very selective molecule, which only shows up in large quantities when life is involved (at least in Earth-like chemistry).

- Until we find a compelling abiotic pathway, high DMS remains a strong biosignature, especially in the context of a planet with a potential ocean and mild temperatures

Possible origins:

We’re looking at some form of life that can:

- Thrive in a hydrogen-rich atmosphere

- Possibly live in or on top of a global ocean

- Generate large amounts of DMS—potentially thousands of times more than Earth

The closest Earth analogy is:

- Marine phytoplankton, particularly species like Emiliania huxleyi, produce DMS as a byproduct of breaking down DMSP, a molecule they use to regulate osmotic pressure and protect against oxidative stress.

- If something similar is happening on K2-18 b, we’d be talking about an ocean teeming with such microbes—perhaps far denser than Earth’s oceans.

Possibly "Giant photosynthetic mats" or sulfuric "algae"

If there’s some landmass or floating structures, maybe the DMS producers are:

- Photosynthetic, sulfur-metabolizing analogues to cyanobacteria

- Living in dense floating colonies or mats like microbial reefs

- Using dimethylated sulfur compounds in their metabolism, and leaking DMS as waste or signaling molecules

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Of course there have been lots of ocean planets in sci-fi literature, but I'm most reminded of the "Pattern Juggler" Planet Ararat from Alastair Reynolds' "Revelation Space" series.

This is incredibly exciting news!

A bit clickbaity of OP to skip the operative word ‘promising’ signs of life.

This is happening 124 light years away from earth.

That means if we develop a way to make a space ship accelerate at 1g for a long period of time, you could go there in just 10 relativistic years.

Unfortunately, whilst science allows such a rocket, our engineering skills are far from being able to build one.