WARNING: The following contains major spoilers for Infinity Wars #6 and Infinity Wars: Fallen Guardian, in stores now.
Drax's journey in the Marvel Universe has been quite a storied one. As the Destroyer, he's had several cosmic adventures, helping the Guardians of the Galaxy safeguard the cosmos time and again. But his main ambition was always to fulfill the reason for which he was created -- to kill Thanos.
In Infinity Wars #6, with Requiem (the evil version of Gamora) having already slaughtered the Mad Titan and created a warped version of reality, Drax ends up sacrificing himself to restore the universe he's loved and protected. However, his fate is left uncertain, as we're not sure whether he's dead or ascended to an even greater purpose.
After meeting the creators of the Infinity Stones, Loki renders all the gems in the multiverse inert, leaving Adam Warlock's Infinity Watch with the only active set he stole from Requiem's Warped World. Warlock and company then use these stones to recreate their original universe and also, showing compassion, they copy the Warped World into a pocket inside the Soul Stone, ensuring all the warped characters get a chance to live on. However, as all this is being done in Soul World, they still need to return to their respective homes.
Drax and his former human form, the sax-playing Arthur Douglas (it's a long story, but they sum it up nicely), rip open two portals (conveniently in the shape of an infinity sign) for everyone to escape. However, someone has to stay behind to hold it open. Drax selflessly volunteers. Adam's team heads back to the main Marvel Universe, thanking Drax for his heroics, while Arthur then escapes into the new Warped World. It's a sacrifice we're not surprised by; even though Drax is one of the galaxy's fiercest warriors, he has always been written as having a huge heart.
In the finale, Adam tells Star-Lord's squad that he doesn't know where Drax ended up, but in the Infinity Wars: Fallen Guardian epilogue, we see he may not be dead after all. This one-shot tribute to Drax recalls how Thanos inadvertently smashed Arthur's car decades ago, killing his family and him, only for Thanos' dad (Mentor) and grandfather (Chronos) to place Arthur's soul into the body of the Destroyer to kill the Mad Titan.
The final page here shows the Destroyer living his best life, brawling with the Kree, Brood, Skrulls and Fraternity of Raptors. It's uncertain, though, if these are flashbacks, visions of the future, a hallucination or Drax in the Soul World living out his fantasies.
Either way, it's bittersweet, because while this Destroyer is enjoying a life of war, Arthur gets a second chance at life in the Warped World. He's back with his wife, who gets pregnant, reliving the old Marvel canon; only this time, it's tweaked to give them a happy ending.
Coincidentally, the warrior Drax did get a brief goodbye with his daughter, Heather (Moondragon), who fell in from another reality to stop Requiem. Her soul was placed in Moondragon's body in the past, but after dying in the main Marvel Universe, Drax hasn't seen her in a while. Nonetheless, Drax is happy and at peace, as he feels like he's wrapped up loose ends.
He got to say goodbye to the ones he loves and is comfortable knowing Thanos is dead. It remains to be seen whether he returns from being left behind in the Soul World for new adventures in Arthur's Warped World, or if somehow Adam can bring him back to the Guardians.