Successful cases of Layer2 projects collaborating with Layer1 blockchains include Arbitrum/Optimism on Ethereum, which enhance scalability via rollups. Lessons: Interoperability is key—ensure smooth asset bridging (e.g., Polygon on Ethereum). Regulatory compliance for Layer2s matters to avoid legal risks. These show that effective Layer1-Layer2 synergy boosts user adoption and token value. For the sector, prioritize projects with strong Layer1 partnerships, proven scalability solutions, and clear governance, as such collaboration drives long-term market confidence and price growth.