Final answer:
The missing punctuation in the sentence should be a comma before the coordinating conjunction 'and'
Step-by-step explanation:
The missing punctuation in the given sentence can be added as follows:
I am going home, and I am not coming back.
In this sentence, the missing punctuation is a comma before the coordinating conjunction 'and'. The comma is used to separate the two independent clauses, making the sentence clearer and easier to read.
Learn more about Punctuation in English sentences