The Download: mysteries of the immunome, and how to choose a climate tech pioneer

Made up of 1.8 trillion cells and trillions more proteins, metabolites, mRNA, and other biomolecules, every person’s immunome is different, and it is constantly changing.

It’s shaped by everything we have ever been exposed to physically and emotionally, and powerfully influences everything from our vulnerability to viruses and cancer to how well we age to whether we tolerate certain foods better than others.

Yet as critical as the immunome is to each of us, it has remained largely beyond the reach of modern medicine. Now, thanks to a slew of new technologies, understanding this vital and mysterious system is within our grasp, paving the way for powerful new tools and tests to help us better assess, diagnose and treat diseases. Read the full story.

—David Ewing Duncan

The story is a collaboration between MIT Technology Review and Aventine, a non-profit research foundation that creates and supports content about how technology and science are changing the way we live.

3 takeaways about climate tech right now

On Monday, we published our 2025 edition of Climate Tech Companies to Watch. Curating this list gives our team a chance to take a step back and consider the broader picture. What industries are making progress or lagging behind? Which countries or regions are seeing quick changes? Who’s likely to succeed?

This year is an especially interesting moment in the climate tech world, something we grappled with while choosing companies. Here are three of the biggest takeaways from the process of building this list.

—Casey Crownhart