Superconductivity and the charge density wave (CDW) are two very different cooperative electronic phenomena. However, both occur because of Fermi surface instabilities and electron-phonon coupling. There are a few CDW bearing materials that are also superconducting and the idea that superconductivity and CDW states are competing electronic states at low temperatures is one of the fundamental concepts of condensed matter. The controlled intercalation of TiSe2 with Cu to yield CuxTiSe2 and now TaS2 with Cu gives rise to a continuous suppression of the CDW transition and a superconducting state emerging. This is analogous to the antiferromagnetic-superconductivity phase diagram of the high temperature superconductors. These systems of CuxTiSe2 and CuxTaS2 provide the good opportunity to study the CDW-superconductivity transition in detail through easily controllable chemical parameter.