The infamous 'Hubble tension’ is a statistically significant mismatch between the value of the Hubble constant measured using the classical distance ladder method and that inferred from the ΛCDM model fitted to cosmic microwave background (CMB) data. Naturally, extraordinary experimental efforts are underway to clarify whether this mismatch could be due to a systematic error. Yet, the fact that several independent local probes of the Hubble constant (although not all) point to a discrepancy has increased the attention given to the possibility that this 'Hubble tension' indicates new physics beyond ΛCDM. After a brief review of the various measurements, I will discuss potential implications that such mismatch could have. I will argue that current data favor the possibility that our Universe has undergone anomalous expansion just before recombination and present an overview of the most promising models. I will show in particular that the Hubble tension could point to the presence of a dark energy component at redshift z ~ 3500. I will show that this `early dark energy’ can lead to a variety of signatures in the CMB and Large Scale Structure data. I will finally discuss implications of the recent cosmic shear measurements for the EDE resolution to the Hubble tension (and more generally for anomalous pre-recombination expansion history).