2001 Subaru wagon pulled codes for camshaft sensor and the catalytic converter

My car was all of a sudden running rough I was
near an auto zone and I pulled the check engine
light codes it came up with both the camshaft
sensor and the catalytic converter. The guy at auto
zone and 2 mechanics I spoke to said 95% of the
time it’s the camshaft sensor that causes it. And to
replace that. The mechanic that replaced it today
said that it may not fix the problem. Would I need
to replace both??