Carl and Negan have only interacted a few times so far on The Walking Dead, but each of those interactions have been significant. In the first, while lined up waiting to see who else might be the victim of Negan's next attack, Carl almost lost his arm. Though the situation proved too traumatic for his father, it left Carl more than ready to fight back. The second time he saw Negan, it was during the raid on Alexandria. Carl pointed a gun at him and issued a warning. Things are definitely contentious between them (that's an understatement), but their relationship develops in interesting ways in the comics and might do so in the show as well. What is Carl and Negan's relationship like in The Walking Dead comics?
Things take a turn in the comics when Carl — still just a little kid and not the very tall teenager Chandler Riggs has turned into — sneaks into one of the Negan's trucks on the way out of Alexandria. This results in Carl opening fire on the Saviors, killing a whole bunch of them, but instead of earning Negan's ire, Negan becomes intrigued. This sets the stage for their relationship going forward and the strange bond they have that is built on both tension and respect.
Afterwards, Negan brings Carl along to the Sanctuary and gives him a tour. Negan is intrigued by Carl's unusual fearlessness for such a young child. Later in the issue, he goads Carl into removing his bandages so that Negan can see his missing eye and bullet wound; he starts to mock Carl, but then an interesting thing happens. Carl begins to cry and Negan actually feels bad; he remembers that Carl is just a child. He ends up returning Carl to Rick unharmed.
Much later on, after Negan is defeated and imprisoned, Carl visits him regularly to talk. He gives Negan updates on his life and seeks advice, almost as though Negan were a friend or even an uncle. However, when Negan asks if Carl still wants to kill him, Carl answers that he does. But, I mean, of course he still does; Carl couldn't easily forget (or forgive) all of the things Negan has done to him and his people.
On the show, some of this storyline seems to have been delegated to Daryl instead of Carl. Daryl is the one who has found himself inside the Sanctuary and is earning Negan's attention and curiosity. Like he did in the comics with Carl, Negan respects Daryl and sees how he can be useful. However, that doesn't mean Carl and Negan's bizarre relationship won't also see screen time as well. Negan's complex connection with the Grimes family becomes important in the comics, so it is likely to be explored on the show as the season progresses.