Currently, there are about 50% of Post-Merge OFAC Compliant Blocks on Ethereum, which means there’s a half of the whole network that doesn’t want to deal with Tornado Cash transactions. For now, they only block such transactions from their own blocks but are still okay to build on top of blocks that include them. However, if pressed to do so by governments or out of an abundance of caution, they might adopt stricter censorship and start refusing to build on top of such blocks as well. That’s the one step needed for Tornado Cash to be fully censored.