[2] On September 16, 2016, OnGameNet, a South Korean cable television channel that specialized in broadcasting video game-related content and esports matches, announced that it would be hosting a 16-team Overwatch league called OGN Apex.

[4] Twelve South Korean teams, Afreeca Freecs Blue, MVP Space, BK Stars, Luxury Watch Blue, Rhinos Gaming Titan, Flash Lux, Mighty Storm, KongDoo Panthera, Kongdoo Uncia, RunAway, CONBOX T6, and Lunatic-Hai, qualified for the main league.

[2] The finals, which took place in Ilsan, South Korea on December 3, 2016, saw Team EnVyUs defeat Afreeca Freecs Blue, 4–1.

[8] English casting duo Mykles and Lonnquist departed from Apex to prepare for Blizzard Entertainment's upcoming Overwatch League.

[1] Returning South Korean teams from Season 2 included Lunatic-Hai, KongDoo Panthera, Afreeca Freecs Blue, RunAway, KongDoo Uncia, Luxury Watch Blue, BK Stars, and Meta Athena, while qualified teams from Challengers included Mighty AOD, X6-Gaming, CONBOX Spirit, MVP Space, Flash Lux, and Rhinos Gaming Wings.

[8] In May 2017, Blizzard Entertainment announced plans to launch Overwatch Contenders, a "development league" in North America and Europe.

[1] Season 4 was contested by MVP Space, Meta Athena, KongDoo Uncia, Flash Lux, Afreeca Freecs, ROX Orcas, Meta Bellum, LW Blue, Lunatic-Hai, RunAway, KongDoo Panthera, NC Foxes, LW Red, GC Busan, X6-Gaming and CONBOX.