There are many ways in which the 2020 NFL season may look different from those played in the very recent past. Empty stadiums would be one potential difference. Whether or not the season is even played is a pretty big one. But even the way the players look could be different heading into this year.
All in an effort to help prevent the spread of the coronavirus, which is obviously a major concern, especially with the virtual impossibility of there being a vaccine available in time for the scheduled start of the NFL season. So the league is doing everything it can to help mitigate that—short of cancelling games, of course.