Tyson Fury, the British heavyweight champion, has declared his retirement from boxing in a video posted on Instagram. The announcement follows his recent losses to Oleksandr Usyk, which ended in a unanimous decision in December, raising questions about his future in the sport. Fury, 36, has previously retired but returned to the ring shortly after making such declarations. Promoters and fans are left uncertain if this retirement will hold, especially amid longstanding hopes for a potential matchup with Anthony Joshua, which now seems unlikely.