Several mixed-gender team events made their debut at Tokyo 2020. For 10 points each:
[10e] Poland won the inaugural mixed relay in athletics, in which each athlete ran this metric distance, the length of a standard athletics track.
ANSWER: 400 metres [accept 4x400m mixed relay]
[10m] As expected, the mixed team archery competition was dominated by this Asian country's team, whose female archers have won every women's team event since it was first held in 1988.
ANSWER: South Korea [or Republic of Korea or ROK or Hanguk or Namhan or Daehan Minguk]
[10h] The new mixed team event in this specific discipline earned San Marino its first ever Olympic silver medal. Shortly prior, Alessandra Perilli had won San Marino's first medal of any colour in the women's event in this discipline.
ANSWER: trap shooting [accept mixed trap team or women's trap; prompt on sport shooting or marksmanship or similar, asking "what specific event?"]