Djokovic has repeatedly refused to disclose his vaccination status and intimated he would not play if the vaccine ruling was enforced
Djokovic is a five-time champion at Indian Wells, lifting the title in 2008, 2011, 2014, 2015 and 2016.
World number one Djokovic would become the first man since Rod Laver in 1969 to capture all four Grand Slam titles in the same year if he captures his fourth US Open title.
Tokyo Olympics 2020: Alexander Zverev hails Novak Djokovic as 'greatest of all time' after overcoming Serb in semi-finals
"He's the greatest player of all time, he will win the most Grand Slams out of anybody on tour, but I'm also happy that I'm in the final," said Zverev.
World number one Djokovic, who has already sealed the Australian Open, French Open and Wimbledon titles this season, brushed aside Nishikori 6-2, 6-0 in just 70 minutes.
Tokyo Olympics 2020: 'Pressure is a privilege', says Novak Djokovic as he aims to keep Golden Slam bid intact
World number one Djokovic is trying to become the first man to win all four Grand Slams and Olympic gold in the same year, and emulate the feat achieved by Steffi Graf in 1988.
Tokyo Olympics 2020: Kei Nishikori hopes Japan's gold rush can inspire him to overcome Novak Djokovic
Nishikori, who earned bronze five years ago in Rio, is aiming to wreck Djokovic's pursuit of a Golden Slam in Tokyo and keep alive his dream of becoming Japan's first Olympic tennis champion.
In Numbers: Novak Djokovic wins Wimbledon, goes level with Roger Federer, Rafael Nadal on 20 Grand Slam titles
With his sixth Wimbledon title, Novak Djokovic equalled the record for most Grand Slams among men with his storied rivals Roger Federer and Rafael Nadal.
The Serb had always insisted he would think twice if the COVID-19 protocols in Japan became too strict and if fans were banned.
Despite his achievements, however, Djokovic appears doomed never to be held in the same saintly esteem reserved for Federer or Nadal, the undisputed 'people's champions' and tennis' go-to good guys.
Minutes after Djokovic's win, Federer sent a congratulatory tweet saying: “Congrats Novak on your 20th major. I’m proud to have the opportunity to play in a special era of tennis champions. Wonderful performance, well done!”
Wimbledon 2021 Live Streaming: When and where to watch men's singles final between Novak Djokovic and Matteo Barrettini online on Live TV
All you need to know about when and where to watch Wimbledon 2021 men's singles final between Novak Djokovic and Matteo Berrettini.
Wimbledon 2021: Novak Djokovic defeats Denis Shapovalov to set up final clash against Matteo Berrettini
In his seventh Wimbledon final, Djokovic will face Matteo Berrettini after the world number nine became the first Italian to reach a Wimbledon singles final by beating Hubert Hurkacz 6-3, 6-0, 6-7 (3/7), 6-4.
Federer turns 40 next month and never was able to summon the serving and shot-making that have carried him to 20 Grand Slam titles overall.
Wimbledon 2021: Novak Djokovic brushes aside Marton Fucsovics in straight sets to reach his 10th semi-final
With the win, Djokovic continued his pursuit of a 20th Grand Slam title overall, which would tie the men’s record currently shared by Roger Federer and Rafael Nadal.
Wimbledon 2021: Novak Djokovic, Roger Federer to light up final 'Manic Monday' as place in quarter-finals beckon
World number one Djokovic, chasing a sixth Wimbledon and record-equalling 20th major, is already halfway to becoming just the third man to complete a calendar Grand Slam.
Wimbledon 2021: Novak Djokovic slides to victory; Tsitsipas crashes and Andy Murray shines as Wimbledon makes soggy return
Djokovic dropped the first set against Jack Draper, but soon snuffed out any danger of him becoming only the third defending champion to lose in the first round, by sweeping through the remainder of the tie.
French Open 2021: Tsitsipas showed he’s ready to take baton from Big 3; Krejcikova’s win demonstrated depth of women’s tennis
Two of the game’s biggest mysteries were solved at the French Open last week: ‘How to beat Rafael Nadal at the French Open' and 'Who will take over the mantle from the big three?'
French Open 2021: Novak Djokovic tops Stefanos Tsitsipas to come within touching distance of Rafael Nadal, Roger Federer
After his semi-final against Nadal, that lasted more than four hours on Friday night, Djokovic looked diminished and depleted at the outset on Sunday. By the end, he was at his imperious best.
French Open 2021: Novak Djokovic, Rafael Nadal set landmarks; Roger Federer, Iga Swiatek, Sofia Kenin win
While World No 1 Novak Djokovic is in the last 16 for the 12th successive year, defending champion Nadal reached the fourth round for a record 16th time.