Challenges of the standard cosmological model

Measurements of the temperature and polarization anisotropy of the cosmic microwave background (CMB) provided strong confirmation of the vanilla flat ΛCDM model of structure formation. Even if this model fits incredibly well, the cosmological and astrophysical observations in a wide range of scales and epochs, some interesting tensions between the cosmological probes, and anomalies in the CMB data, have emerged. These discrepancies have different statistical significance, and although some parts may be due to systematic errors, their persistence strongly indicates possible cracks in the standard ΛCDM cosmological scenario.