The 1999 Porsche Tennis Grand Prix – Doubles was the tennis doubles event at the 1999 Porsche Tennis Grand Prix, the twenty-second edition of the most prestigious tournament in Baden-Württemberg.
 Lindsay Davenport and Natasha Zvereva were the defending champions, but they did not compete this year.
 Davenport competed with Martina Hingis as the first seed, while Zvereva competed with Elena Tatarkova.
 Davenport and Hingis withdrew in the quarterfinals due to Davenport having a wrist injury, whilst Tatarkova and Zvereva were knocked out in the first round.
Roger Federer won one slam in 2008, which came at the 2008 US Open, defeating Briton Andy Murray, 6–2, 7–5, 6–2.
 Federer was defeated by Rafael Nadal in two Grand Slam finals: at the 2008 French Open, which he lost 1–6, 3–6, 0–6, and at the 2008 Wimbledon Championships in a five-setter, 4–6, 4–6, 7–6, 7–6, 7–9, when he was going for six straight wins to break Björn Borg's record.
 At the 2008 Australian Open, Federer lost in the semifinals to Novak Djokovic, ending his record of 10 consecutive Major finals.
 Roger Federer lost twice in Master Series 1000 Finals on clay to Nadal at Monte Carlo and Hamburg.
 However, Federer was able to capture three more victories in 250-level events at Estoril, Halle, and Basel.
Martina Hingis and Jana Novotná were the defending champions, but they did not compete together this year.
 Novotná instead partnered with Natasha Zvereva as the first seed, whereas Hingis partnered with Anna Kournikova as the second seed.
 Novotná and Zvereva retired in their quarterfinal match against Lindsay Davenport and Mary Pierce, but Hingis and Kournikova reached the final where they lost to American sisters Serena and Venus Williams, 6–3, 6–7, 8–6.
 This was the first Grand Slam for the Williams sisters and would be their first step towards completing a Career Golden Slam in doubles.
Gigi Fernández and Natasha Zvereva were the defending champions but they competed with different partners that year, Fernández with Martina Hingis and Zvereva with Lindsay Davenport.
The 2016 Roger Federer tennis season officially commenced on 3 January 2016 with the start of the 2016 Brisbane International.
 This season saw Federer suffer from a knee injury which sidelined him for the majority of the year.
 After having surgery, Federer returned but was hindered by a back injury which kept him out of the French Open, therefore ending his record of 65 consecutive appearances at Grand Slams.
 Federer played his last match in the semifinals at Wimbledon.
 On July 26, Federer shut down his season, not wanting to risk damaging his knee further.
 Federer would end the year at No. 16, marking the first time that Federer dropped out of the Top 10 since 2002.
 It also marked the first time since 2000 that Federer did not win a title.
Lindsay Davenport and Natasha Zvereva were the defending champions, but Davenport did not compete this year.
 Zvereva teamed up with Katarina Srebotnik and lost in quarterfinals to Lisa Raymond and Rennae Stubbs.
Roger Federer (] ; born 8 August 1981) is a Swiss professional tennis player who is currently ranked world No. 2 in men's singles tennis by the Association of Tennis Professionals (ATP).
 Federer has won 19 Grand Slam singles titles, the most in history for a male tennis player and has held the world No. 1 spot in the ATP rankings for a record total of 302 weeks, including a record 237 consecutive weeks.
 After turning professional in 1998, he was continuously ranked in the top ten from October 2002 to November 2016.
Natasha Zvereva, or Zverava, (born Natallya Maratawna Zverava; Belarusian: Наталля Маратаўна Зверава; 16 April 1971) is a former tennis player from Belarus.
 Zvereva was the first major athlete in the Soviet Union to demand publicly that she should be able to keep her tournament earnings.
 The team of Zvereva and Gigi Fernández won more women's doubles titles and Grand Slam women's doubles championships than any other team since that of Martina Navratilova and Pam Shriver.
Gigi Fernández and Natasha Zvereva were the defending champions but only Zvereva competed that year with Lisa Raymond.
The 2017 Australian Open Men's Singles final was the championship tennis match of the Men's Singles tournament at the 2017 Australian Open.
 It was contested between Roger Federer and Rafael Nadal, ranked 17th and 9th in the world respectively.
 It was their record ninth meeting in a Grand Slam final in their rivalry, and their 1st meeting in a Grand Slam final since the 2011 French Open.
 In a rematch of the 2009 Australian Open final, which Nadal won in 5 sets, Roger Federer won the duel in 5 sets, beating Nadal for the first time in a Grand Slam since the 2007 Wimbledon final.
 He also trailed Nadal 3–1 in the final set but won 5 games in a row to win the title.
 This ended a 6-match losing streak against Nadal in Grand Slam events.
 Having lost all of their previous three encounters, this was the first time Federer defeated Nadal at the Australian Open and also marked Federer's first Grand Slam victory over Nadal outside the grass courts of Wimbledon.
 Federer extended his record of Grand Slam men's singles titles to 18, marking the third time he broke his own all-time record, after breaking the previous record of 14, held by Pete Sampras.

Question: What do Roger Federer and Natasha Zvereva have in common?
Answer: tennis player