CI originates with an extreme programming development process which is one of its original twelve practices. It doesn't require you to deploy any particular tools but it is useful if you use a CI server.
CI means the developer can constantly merge their work with the master/main/trunk branch, so it will be easier for the Test team to test the latest changes with the existing changes. It will help to test code as soon as possible and provide rapid feedback, so that any issue can be identified and fixed as soon as possible. In this process, most of the work is done by automated tests which are part of the unit test framework.
The following is a pictorial representation of CI. In this process, ...
