Kendrick Lamar and SZA have some of the biggest songs in the world. Kendrick played the Super Bowl after icing out the other biggest rapper in the world . SZA is the co-star of a hit movie , to go with her musical success. Their joint Grand National Tour , which began on April 20, feels like the next logical step toward world domination. But stadium tours are different —like touring on God mode—and, after years of arena shows, it’s the first time they’ve each played the country’s biggest venues.