Confidence contours (68 and 95%) in the Ω_m − σ₈ plane for various datasets: Planck 2015 and 2018 CMB data, and Planck 2015 SZ cluster counts (using the D16 mass function). Contours are shown for the minimal neutrino case and three neutrinos with free masses (using the CDM prescription for cluster counts). For SZ clusters, the calibration parameter (1 − b) is fixed to its fiducial value of 0.8, with priors added to Ω_b from BBN constraints, and to H₀ from BAO data. Two additional dashed and dash-dotted contours are shown to illustrate the effects of changing the mass function used (from Despali et al. 2016 to Tinker et al. 2008) and removing the CDM prescription, respectively.