Inverse-distance-ladder constraints on H₀ and Ω_m in ΛCDM (for more details see Planck Collaboration IV 2020). The green region uses BAO constraints on the distance-redshift relation relative to the sound horizon at the drag epoch. The sound horizon has been constrained here using a conservative prior of ω_b = 0.0222 ± 0.005, based on Cooke et al. (2018) and standard BBN. Adding Planck CMB lensing gives the grey contours, which pull to lower H₀ and Ω_m. The red contours show instead the addition of a highly conservative prior of 100 θ_MC = 1.0409 ± 0.0006, which provides similar H₀ constraints to the full CMB data set, but is potentially more robust. The blue band shows the ΛCDM fits to the full CMB data set. The horizontal grey bands show the measurement of Riess et al. (2019) for comparison.