WWE were working without a crowd in the arena for some time because of the Coronavirus situation. The shows were taking place in the Performance Centerand the ring was surrounded by empty chairs for over 2 months.
Things have changed now and they have introduced NXT talents as the crowd to build the atmosphere. For every show, there are several talents sending around the ring behind a glass wall for the entire show.
The Undertaker has not been able to experience this but worked without a crowd in the buildup to WrestleMania. He had a segment where he was supposed to sign the match contract with AJ Styles but was alone in the ring.
Karl Anderson and Luke Gallows made their way to the ring later and the Phenom attacked them. Talking about WWE working without a crowd, he said:
"I think they're making the best out of a really horrible situation. Obviously you feed so much off of your audience and you use their energy a lot to propel you through your promos and your matches and you can still see during the shows sometimes they can't help it. They look to the crowd and it's an empty warehouse, it's so bizarre."
[H/T WrestlingINC for the quotes]
The match between AJ Styles and The Undertaker did not take place at the Performance Centre. It was shot at an empty warehouse but still did not have fans anywhere near the place.
The Boneyard match was one of the best matches in WrestleMania history and something WWE would not have done if it wasn't for this pandemic. Talking about the same, The Undertaker previously said:
The idea was thrown at me at doing something off-site. I was like, Yeah, that's a much better option than trying to have a match that AJ and The Undertaker would have inside an empty arena. In our case, we were very fortunate to go off-site and do what we did.
"The final product — I couldn't be more proud of it. Under the circumstances, all the different things going on, everybody pulled together and put something like that out there that was different and was intriguing. I can't speak for AJ, but I'm very proud of what we did.”
WWE have been teasing another match between two Superstars but nothing has been set just yet.