Hinata and Kenma are both volleyball player at different high schools, while Kenma is a second year setter at Nekoma, Hinata plays as a first year middle blocker for Karasuno. They first meet when Hinata accidentally runs off track during practice with his team. They talk a bit, Hinata immediately noticing Kenma's shy nature, but he still holds a friendly conversation with him. When Kenma gets picked up by Kuroo, he states that they'll see each other again soon. Hinata is confused at first, but understood what he meant when they saw each other again at the practice match between Nekoma and Karasuno. After said match, Hinata promised to make Kenma say that volleyball is fun and also beat him one day.
They're shown to be good friends over the course of the manga and anime. Both call each other by their first names, as well as text each other regularly about matches and other ordinary things.
Kuroo was impressed that Hinata got Kenma to practice with him at their summer training camp in Tokyo together. He has also stated that Kenma always looks excited when he watches Hinata play. However, Kenma said he wouldn't want to be on the same team as Hinata as his dedication and passion was too much for his rather relaxed and calm personality during game play.
On AO3, KenHina is the second most written ship for Hinata and the second most written for Kozume.