Mixers or tumblers are services that allow users to mix their Bitcoin transactions with those of other users to obscure the source and destination of funds. While mixers can be useful for maintaining privacy, there are also some potential dangers associated with using them. There are several services that claim to offer this level of security, but it is important to be careful of any claim that the mixer is completely secure or anonymous and at worst is blacklisted by exchanges and other service providers.
Any person who have use mixer or tumbler know if centralized exchange, bank, and government are blacklist mixing usage because it can be used to money laundering. This is we have an option to use decentralized exchange and cash out without bank, but it's hard since you need to find someone who's willing to trade with you. Mixing isn't make your transaction secure, but it just to increase your privacy into 100% anonymity.