FISA 702 and Executive Order 12333 were identified by the ECJ in Schrems II as being potential obstacles to ensuring essentially equivalent protection for personal data in the US:
FISA Section 702 (“FISA 702”) – allows US government authorities to compel disclosure of information about non-US persons located outside the US for the purposes of foreign intelligence information gathering.  This information gathering must be approved by the Foreign Intelligence Surveillance Court in Washington, DC.  In-scope providers subject FISA 702 are electronic communication service providers (“ECSP”) within the meaning of 50 U.S.C § 1881(b)(4), which can include remote computing service providers (“RCSP”), as defined under 18 U.S.C. § 2510 and 18 U.S.C. § 2711.
Executive Order 12333 (“EO 12333”) – authorizes intelligence agencies (like the US National Security Agency) to conduct surveillance outside of the US.  In particular, it provides authority for US intelligence agencies to collect foreign “signals intelligence” information, being information collected from communications and other data passed or accessible by radio, wire and other electromagnetic means. This may include accessing underwater cables carrying internet data in transit to the US.  EO 12333 does not rely on the compelled assistance of service providers, but instead appears to rely on exploiting vulnerabilities in telecommunications infrastructure.
Further information about these and other US Surveillance Laws may be found in the U.S. Privacy Safeguards Relevant to SCCs and Other EU Legal Bases for EU-U.S. Data Transfers after Schrems II whitepaper (published by the US Department of Commerce, Department of Justice, and Office of the Director of National Intelligence), which discusses the limits and safeguards relevant to US public authority access to data in response to Schrems II.