Does Ethereum still use PoW?

I'm curious about the consensus mechanism behind Ethereum, as the landscape in crypto is constantly evolving. So, I'd like to ask: Does Ethereum still utilize Proof of Work (PoW) as its consensus mechanism? If not, what has replaced it? And how has this transition impacted the network's security, scalability, and energy efficiency? Understanding these changes is crucial for investors, miners, and developers alike. Any insights you could provide would be greatly appreciated.