PewDiePie recently came back to Twitch, but not in the way you'd expect. He wasn't streaming live content but instead running a loop of all his YouTube videos, signified by a new logo using the infinity symbol. However, as of today, his account has been banned for breaching Twitch's terms of service.
It's unclear how he breached the TOS, but plenty of fans have their own theories. Some believe that the infamous clip of PewDiePie on the bridge in PUBG cropped up in which he yells the n-word after being attacked. However, his Twitch channel is managed by CoPilotMedia who would have likely removed it from circulation.... if it was even there in the first place. It may not have been available since it took place in a YouTube stream.
Another theory is that it was taken down for streaming full episodes of Trailer Park Boys. Fans noticed this back in March, believing that he had been hacked. He wasn't. The show was played by his partner CoPilotMedia whose website lists several studios, shows, and creators that it's "trusted by". These include Trailer Park Boys, Wiseau Films, Alf, PewDiePie, and The Room.
It's possible that the ban was due to a copyright claim, similar to what happened during the 'TV Show Meta' of January 2022 in which several high-profile streamers watched full episodes on their channels. It started off with Gordon Ramsay's MasterChef, but ended up with creators watching full episodes of Avatar: The Last Airbender. It grew so bad that Pokimane received a DMCA during one of her streams, so hosting full episodes of Trailer Park Boys might have had similar consequences for CoPilotMedia and PewDiePie.
Another belief, highlighted on the LivestreamFail subreddit, is that the channel was breaching the new 'branded content policy' in which you have to flag all sponsors and brands you work with. While it's known PewDiePie works with CoPilotMedia for his Twitch channel, old videos and clips are filled with sponsors, all of which are likely undeclared. This may throw a wrench in the works of the whole infinite loop concept.
We don't know the exact reason for the ban, and neither PewDiePie nor CoPilotMedia has made a statement yet addressing the situation. Regardless, the channel will likely be back up soon as it's not a permanent suspension, and it's the first in the channel's history.