When things will finally get back to what it used to be on a global level and large crowd gatherings will be safe to hold, it would be nice to have a globally synchronized event to mark the end of the pandemic. That the end of this will feel like a celebration is what everybody is thinking, but I didn't hear an idea to make an actual event expressed yet. And that is, of course, understandable, because it's not what mental and physical efforts should be focused on right now, but since the vaccination process is slowly picking up speed, I think it's not too early to start thinking about it. Having something to look up to helps withstand the hardship.
Each country could hold its own event, but they all could be centralized, synchronized, and live-streamed online for people around the world to watch. This would add up to strengthening collective humanity's spirit after the common crisis. Maybe a year from now is a reasonable time to consider and if things will go favorably, maybe even the summer of 2021.
Of course, some countries will get out of the crisis later than others, it can take especially long for the least developed countries, but those should receive help from the developed ones especially when the situation will become stable in most of the world. Another obstacle to this might be that people who lost their family members and friends because of the virus might be dissatisfied with such an event, but I think it would all depend on how it is presented, the commemoration of the victims should be a part of it.