The closed nature of the Soviet state made it extremely hard — nearly impossible — for the US to take foreign agents and insert them into the USSR. (They did attempt this in the eastern block in the early Cold War; they were quickly discovered and shot.) This is a fundamental asymmetry in how the US and the USSR collected intelligence information — the USSR could rely on human networks much better than the USA could. The Americans did have some human intelligence sources (e.g. recruits or volunteers) but not to the same depth as the Soviets (and many of the ones they had were compromised by Soviet spies such as Aldrich Ames). This is one of the reasons the US put so much effort into technical intelligence like reconnaissance, wiretapping, decryption, and the like. There were a few high-level Soviet officials who gave information to the USA, but it was not like the Illegals program which involved inserting Soviet agents into the USA under false identities, something that worked because of the relative freedom in the USA.