More than four years after a much-ballyhooed entry into mobile gaming, industry giant Nintendo Co. remains bereft of a monster smartphone hit. But the wait may finally be over.

Mario Kart Tour, set to launch this summer, has had gamers' attention since it was announced in early 2018. Not only is the franchise one of the best-known video game racing series, it's regarded as the Nintendo title most suitable for smartphones in terms of controls, opportunities to make generate revenue from users and features likely to hook mobile players.

But investors remain cautious, given Nintendo's patchy track record in mobile and the fact that Tour was already delayed once. That's why most Wall Street analysts have excluded it from their profit estimates for this year, leaving a lot of upside. Should the game become a bona fide hit, that could be key to sustaining this year's 32 percent stock rally.