Currently, to say a World Cup game is a football/soccer game, one must list at least one team or competitor and then use the http://schema.org/sport property there. It would be nice to support the simplified case of:
{
"@context": "http://schema.org/",
"@type": "SportsEvent",
"name": "World Cup 2018",
"sport": "https://www.wikidata.org/wiki/Q2736",
"startDate": "2018-06-14",
"endDate": "2018-07-15"
}
To support this, we would need to add https://schema.org/SportsEvent to the domain.