1T-TiSe2 has been widely studied in the past few decades as one of the typical charge density wave (CDW) materials. Recently, superconductivity was realized in this system through Cu intercalation, pressure or electric gating, forming a dome-shaped superconductivity phase diagram. Owing to this resemblance to high -Tc cuprates, much attention has been paid to 1T-TiSe2 to understand the superconducting mechanism and its interplay with CDW. However, it is still under debate whether CDW competes with superconductivity or not. Via tuning the dopant level, 1T-TiSe2 system can undergo the transition from CDW to superconductivity, and thus provides an ideal platform to study the relationship between these two states.