Checkpoint inhibitors, like Merck’s Keytruda, have revolutionized immuno-oncology, but response rates have plateaued at 30%. A decade of research has led to a deeper understanding of cancer biology, setting the stage for a second wave of IO therapies, potentially driven by smaller biotech companies. This new wave will explore additional pathways beyond PD-1, with bispecifics and ADCs showing promise. The potential for cytokines and multi-specific antibodies offers hope for more effective, targeted cancer treatments.