Old school or new school? That’s the decision facing celebrants of International Jazz Day in Kansas City on Thursday, April 30. Traditionalists are likely to favor The Count Basie Orchestra in the big band’s return to the Music Hall. Keyon Harrold, a trumpeter who integrates hip-hop and R&B into his jazz-based music, headlines an event overseen by the Mutual Musicians Foundation. The host promises attendees will join “a curated audience of creatives, professionals, tastemakers, and culture leaders.”