CVX is the native platform token for Convex Finance.
CVX can be staked on Convex Finance to earn a share of Curve LP's CRV earnings.
Staked CVX will receive its portion of the fees as cvxCRV (tokenized veCRV). This is to keep CRV in the system building boost, but users can trade out their cvxCRV through the cvxCRV/CRV liquidity pool.
Convex CRV fees that would be returned to CVX stakers are locked in veCRV, and tokenized as cvxCRV and given to the CVX stakers.
CVX is used for voting on how Convex Finance allocates it's veCRV towards Curve.fi gauge weight votes. Users must vote-lock their CVX tokens in order to participate. Full details on the "Voting and Gauge Weights" page