Ever since One Piece's Dressrosa arc, fans have wondered when (and what) Luffy's Devil Fruit would awaken. First introduced through antagonist Donquixote Doflamingo, as strong as Devil Fruits can be, they all have the potential to evolve and become even stronger. This process is called "awakening." First shown off by Doflamingo and later elaborated on by Katakuri, their awakenings allowed them to have complete control over their environments.
In Chapter 1030 of the One Piece manga, readers were shocked to find out Eustass Kid and Trafalgar Law had also awakened their fruits, albeit not with the mastery level that Doflamingo and Katakuri had. While their abilities did grow, Kid and Law both stated that using their awakened abilities would drain their stamina greatly, putting them in a vulnerable state. It might be a coincidence, but the drawbacks to using their awakened abilities are quite similar to what happened when Luffy first created his different gears.
First unveiled after the Straw Hats made it to Enies Lobby, the Gears were notable as the first real power-ups Luffy had ever had in One Piece. With Gear Second, he increases his blood flow by using his rubber body and cells to force more blood through his vessels. Doing this greatly enhances Luffy's physical abilities to the point that CP-9 agents would have trouble keeping up with his speed and strength. Though it's a great enhancement, relying on it would drain his body of its nutrients, weakening him significantly. Rob Lucci pointed out how the process was similar to doping, and could decrease his lifespan if used too much and incorrectly.
Gear Third unfortunately came at a price as well. By biting his thumb down to the bone and blowing into it as hard as he can, Luffy could inflate one of his limbs until they were as large as a giant's, if not larger. While it was hard to move around in this form at first, the real problem was that once the effect wore off, Luffy would "deflate" and become a fraction of his normal size, making him much weaker and more vulnerable.
With the drawbacks of these two Gears, Luffy has wisely only used them when he felt it necessary. During his fight with Lucci, he learned the hard way that overusing either could easily lead to his death. This is practically the same as when Law and Kid used theirs against Big Mom, as their bodies became much weaker and and exhausted from using such advanced techniques.
Law and Kid's Devil Fruits are different, as their powers need to be consciously activated as opposed to Luffy's permanently transformed body. This could explain the slight differences between their respective drawbacks, though Luffy has managed to overcome the weaknesses of his Second and Third Gears after training during the timeskip. Considering that Doflamingo and Katakuri are veteran pirates who had decades of experiences to train and acclimate to their Devil Fruit's awakened powers, it makes sense that they wouldn't feel drained from using them -- just like Luffy no longer does.
Then there's Gear Fourth, the most powerful but complicated of the bunch. Similar to Gear Third, this form involves Luffy biting into the muscles in his arm after they've been coated in Armament Haki. This expansion of the muscles while they're coated and compressed gives him explosive physical power and made him strong enough to take out both Doflamingo and Katakuri. The downside to this gear, however, is that he cannot use his Haki for around 10 minutes and is completely exhausted.
Since Gear Fourth combines Luffy's Devil Fruit and Haki abilities into one, it's hard to use it as an example of a possibly awakened ability. On the other hand, because it is in many ways a variation of Third Gear, it shouldn't be ignored -- and both Katakuri and Doflamingo could combine Haki with their awakened abilities. Conveniently, just like Third Gear, Luffy's body seems to be acclimating to this form more and more with each use; he was recently able to enter and and exit the form without any cooldown period.
All of this could lead to the conclusion that Luffy has managed to at least partially awaken his Devil Fruit. It might not support the "Rubber World" theory that many One Piece fans have bought into, but it does support a different idea about his awakening. Given how his Devil Fruit only really affects his body, it's quite possible that instead of turning things into rubber, Luffy would instead gain greater control over his rubber body. If this were the case, then Luffy could activate these abilities without any extra effort -- as well as use normal abilities without needing a charge-up to stretch out his strikes.
Luffy is primed to have an awakening at some point in One Piece, even if fans can't necessarily guess with certainty what it will end up being. What is for certain is that when it happens, it will bring Luffy one step closer to being the King of the Pirates.