Public cloud hyperscalers have risen to become principal enterprise strategic partners. They wield a new power that forces even the largest global systems integrators (GSIs) to reappraise traditional boundaries, roles, budgets, organizational structures, and decision-making. Current engagement trends indicate that hyperscalers rival — and in some cases exceed — GSIs in how enterprise IT strategies perceive their significance. This report digs into these trends and helps technology and sourcing leaders understand how to navigate this dynamic strategically.