To meet the demands for 6G mobile communication, some novelconcepts were proposed recently, such as the use of reflective intelligent surfaces to control the propagation properties of the environment, and integration of sensing and communication functions to optimize the spectrum usage and energy efficiency. Signal processing in RIS-enabled ISAC systems involves adaptive beamforming, channel estimation, and waveform design, optimizing the reflection properties of RIS elements to improve data transmission and environmental sensing. Advanced algorithms are employed to control the phase shifts and amplitudes of the RIS units, enabling precise manipulation of the propagation environment. This integration facilitates applications like high-accuracy localization, real-time environmental monitoring, and robust network management. Key challenges include developing efficient algorithms for real-time control and addressing the complexity of joint sensing and communication signal processing.