In answer to this question-

There is a Netflix drama called ‘True Story’. ‘The Kid’ is a character in this drama played by Kevin Hart.

The series depicts his role Kid, a comedian who is forced to address the question of how far he would go to safeguard the things he has in life while on tour in his hometown of Philadelphia.

And you might know that Hart’s first stand-up performance, as Lil Kev, took place at The Laff House in his hometown of Philadelphia, and it did not go well.

Also, ‘True Story’ writer Eric Newman revealed that the character was written as being close to Hart but forced to become more desperate due to terrible circumstances.

As people find similarities between the character ‘Kid’ with Kevin Hart so they call him ‘Kid’.