Hypothesis
Extending the cosmological constant to wCDM, w0waCDM, scalar-field or interacting dark energy would bring the inferred Hubble constant into agreement with local measurements.
What failed
With DESI DR2 baryon acoustic oscillations, Pantheon+ supernovae and Planck and ACT cosmic microwave background data, the inferred Hubble constant came out consistent with early-universe values in all five models, leaving the tension exactly where it was, even though the same data favoured an evolving equation of state and a late-time dark-sector interaction.
Broken assumption
Freeing the dark energy equation of state, or coupling dark energy to matter, relieves the Hubble tension.
Why
The authors report the tension as persistent across the whole model space tested, without identifying what would relieve it.
From the published paper: Zhang et al. The Astrophysical Journal, 2026. ↗CC BY