Comparison of marginal posterior distributions of the reionization optical depth from Planck 2018, shown on the left (red, dotted; Planck Collaboration VI 2020), 9-yr WMAP (green, dot-dashed; Hinshaw et al. 2013), Planck DR4 (cyan, dotted; Tristram et al. 2022), Planck HFI (purple, dot-dashed; Pagano et al. 2020), WMAP Ka–V and LFI 70 GHz (fitting τ + A_s; Natale et al. 2020; blue, dashed); and BEYONDPLANCK using multipoles ℓ = 2–8, marginalized over the scalar amplitude A_s (black). Corresponding marginal BEYONDPLANCK tensor-to-scalar ratio posteriors derived using BB multipoles between ℓ = 2–8, marginalized over the scalar amplitude A_s (gray), and by fixing all the ΛCDM parameters to their best-fit values, shown on the right (black). The filled region corresponds to the 95% confidence interval.