Trump isn't the first president to be subpoenaed by Congress: Here are the others
The House committee investigating the Jan. 6, 2021, riot on Capitol Hill unanimously voted on Thursday to subpoena former President Donald Trump, escalating the panel's efforts to dig into the impetus and impacts of the insurrection.
-snip-
John Tyler and John Quincy Adams
Congress subpoenaed the two presidents after they had already left office. The orders for testimony in 1848 stemmed from accusations by the House Committee on Foreign Affairs that then-Secretary of State Daniel Webster misused money for a secret "contingent fund" used by presidents for clandestine intelligence operations.
-snip-
Harry Truman
The infamous House Committee on Un-American Activities, which reached its height during the Cold War-era Red Scare, subpoenaed former President Harry Truman to get information on his "Loyalty Program," which was intended to root out anyone loyal to the Soviet Union.
-snip-
Richard Nixon
Nixon was actually subpoenaed twice by Congress, both in relation to the Watergate scandal.
https://www.msn.com/en-us/news/politics/trump-isn-t-the-first-president-to-be-subpoenaed-by-congress-here-are-the-others/ar-AA12W9so