Amid controversy surrounding the alleged murder of journalist Jamal Khashoggi, SoftBank chief Masayoshi Son, one of Saudi Arabia's biggest business partners, has cancelled plans to speak at a major investment conference in Riyadh. In the latest high-profile executive to boycott the Future Investment Initiative, known as “Davos in the desert”, Mr. Son, whose giant tech investment fund has received billions from the Saudi Public Investment Fund is one of them.