That depends. I have 3 older ICE vehicles, here in California. A 1966 which is currently exempted from Smog testing. But the other two, a 1995 and 2001, have had issues in passing Smog testing this past year. The rules keep changing. For the first ten years or so, I didn't have to get the 2001 truck Smog tested because it was considered of commercial use. Then the rules changed, and I had to have it tested every 2 years. The rules have changed, tightening restrictions on emissions and making it more difficult to pass. No pass, then no registration for operating on roads.
I didn't have a problem until this past year, where they failed the test and I had to seek resolution. Got them to pass on the 3rd test. I don't know if they'll pass a couple years later. The government will keep ratcheting up the rules until these cars are eliminated from being used on the road.