How a test framework behave when we add a new test case in the middle of the existing test cases?

I have a questions on automation framework, Suppose i have 1000 test cases. I am adding a new test case in the middle.

e.g. I have 1000 test cases. I am adding a test case in the middle (501th). What are some of the issues i may faced in the framework?

-- I am expecting it may break the execution order if all 1000 TCs have some dependencies among themselves. Apart from this issue i am not able to figure out any other possible issues, please help me in identifying the issues that can cause problem in execution of all the TCs here.