Tears of the Kingdom producer Eiji Aonuma rules out the possibility of DLC for the game
In the interview, both Aonuma and Fujibayashi talk about how the early stages of development begun, starting right after the additional content (DLC) for Breath of the Wild was finished, and then going through how the new abilities for Link came into fruition, like Ultra Hand and Autobuild, the newly added caves and underground areas, as well as the sky sections, the Zonai's introduction as well as their devices, the trials, Dungeons, Koroks, Ganondorf's inclusion, amongst many other interesting topics regarding the new entry in the Zelda franchise.
One point of interest from this interview, however, is when both Aonuma and Fujibayashi were asked about a possible sequel or even new "stages", to which Aonoma replies that they currently have no plans for any kind of additional content, given that they chose to make a sequel with the reasoning that they could still add new experiences and ways to play in this new Hyrule from where they left off with Breath of the Wild.
Here's the full section talking about the additional content from the interview, but be aware that the original interview by Famitsu was written in full Japanese, so this translation might not be 100% accurate:
Famitsu's Interview said:-Now then, I'd like to hear about your next work... I think there are various possibilities, whether it's a further sequel or a new stage.
Fujibayashi: I don't know if it will be the next work, but I'm thinking about what the "next fun experience" will be. I can only say that I do not know at the moment what form it will take.
Aonuma: There are no plans to release additional content at this time, but that's because it feels like we've done everything we can to create games in that world. In the first place, the reason why we chose this time as a sequel to the previous game is because we thought there would be value in experiencing new play in that place in Hyrule. Then, if such a reason is newly born, it may return to the same world again. Whether it's a sequel or a new work, I think it will be a completely new way to play, so I'd be happy if you could look forward to it.
If you're interested in reading the full interview by Famitsu, be sure to check out the source link at the bottom, and if you're a native Japanese speaker willing to polish up the translation, be sure to do so on the comments. Any corrections to the interview's translation will be added accordingly and with proper credits.
Source