When a crypto project enters the market, the circulating supply of its tokens is limited: the team, various levels of investors, employees, etc., do not have tokens on hand to avoid creating additional pressure on the coin's price.

According to the schedule defined in the project's tokenomics, these participants start receiving tokens and can sell them on the market. This process is called token unlocking.

Shorting after an unlock is an old but always relevant way to make some profit.