  Observations of the cosmic microwave backgroundradiation are described to
remarkable accuracy by the six-parameterLambda CDM cosmology. However, the key
ingredients of this model, namely dark matter, dark energy and cosmic inflation
are not understood at a fundamental level. It is therefore important to
investigate tensions between the CMB and other cosmological probes. I will
review aspects of tensions with direct measurements of the Hubble constant H_0,
measurements of weak gravitational lensing, and the recent hints of evolving
dark energy reported by the Dark Energy Spectroscopic Instrument (DESI)
collaboration.
