Sony‘s (NYSE:SNE) stock surged 40% to its highest level in nearly two decades in 2019 as the growth of its image sensor business offset the softness of its gaming and consumer electronics divisions. Investors might be itching to take profits after that historic rally, but I believe the stock could still head higher in 2020, for four simple reasons.That paradigm shift caused orders for Sony’s image sensors to surge even as smartphone shipments remained sluggish. In the first half of fiscal 2019, Sony’s I&SS revenue grew 19% annually, making it the company’s fastest-growing unit. Its operating profit grew 63% and accounted for a quarter of Sony’s operating income. Sony expects the unit’s revenue and operating income to grow 18% and 39%, respectively, in fiscal 2019, which ends on March 31. Sony’s I&SS chief Terushi Shimizu recently told Bloomberg that the unit still “can’t make enough” image sensors to meet market demand even as it runs its manufacturing plant 24 hours a day — which suggests that it will continue to be Sony’s core growth engine throughout 2020.Those forecasts are bleak, but the growth of Sony’s I&SS and Music units should help it tread water throughout the rest of 2019 and the first half of 2020. However, the unit should receive a big boost in the second half of fiscal 2020 when its eagerly anticipated PS5 hits the market. Sony hasn’t officially revealed the PS5 yet, but it’s expected to be a significantly more powerful console that will be able to go toe-to-toe against Microsoft‘s ( NASDAQ:MSFT) Xbox Series X during the holidays. Both companies are counting on their next-gen consoles to reboot their sluggish gaming businesses. Sony already shipped over 100 million PS4s over the past six years, making it the world’s top console maker and one of its top game publishers. This gives Sony an edge against Microsoft, and a warm reception for the PS5 at the end of the year could propel its stock to fresh highs by 2021.