  In Vehicle-to-Everything (V2X) systems, reliable and secure information
exchange plays a pivotal role in road safety and traffic management. Due to the
open nature of the wireless medium and the constant or intermittent mobility of
vehicles, the security of transmissions in V2X is more challenging compared to
traditional wireless networks. Physical layer security (PLS) leverages the
inherent randomness of wireless communication channels to ensure the
confidentiality and security of information transmission. Current PLS schemes
in integrated communications and sensing (ISAC) enabled V2X systems is to
utilize communication interference to significantly impact the eavesdropping
channel more than the legitimate channel. However, in an ISAC-enabled V2X
system, it is crucial to prioritize and address the issue of interference
coupling as it significantly impacts the confidentiality and security of
information exchange. This goes beyond simply relying on the communication
interference. Until now, no discussions or studies on integrating security with
ISAC (Seucue-ISAC) in ISAC-enabled V2X systems, specifically regarding the
exploitation of sensing interference or coupling interference. In this article,
we provide a comprehensive review on PLS metrics and security threats
encountered in V2X communication. And then, we discuss and analyze four popular
PLS techniques and the main challenges associated with their implementation in
ISAC-enabled V2X systems. Finally, we share our vision for PLS studies in
ISAC-based V2X systems to promote Secure-ISAC.
