TuTuApp Helper is basically just another Cydia AppStore with lot of apps and tweaks inside it. It allow users to download the available Cydia tweaks and apps for free.
Since Jailbreaking iOS 11 has became a very difficult task, users have started installing modified apps on their iDevices using Cydia Impactor. However, the issue with sideloaded apps is getting revoked. It is because they have a limited duration Apple developer license and once it is expired, users have to re-install or sideload these apps using Cydia Impactor.