Lung cancer persists as a leading cause of cancer-related mortality globally, a dire statistic driven predominantly by late-stage diagnosis. Current screening and diagnostic methods, including low-dose computed tomography (LDCT) and tissue biopsy, are hampered by high false-positive rates, invasiveness, and an inability to fully capture tumor heterogeneity. The emergence of liquid biopsy, which analyzes tumor-derived components in biofluids, presents a transformative opportunity for non-invasive, comprehensive cancer diagnostics. Within this paradigm, microRNAs (miRNAs) and proteins have emerged as powerful complementary biomarker classes; miRNAs offer insights into the regulatory underpinnings of tumorigenesis, while proteins reflect the functional proteomic state of the tumor. However, single-analyte approaches fail to leverage the biological synergy and cross-validation potential of these molecules. This review comprehensively synthesizes the burgeoning field of integrated miRNA–protein dual biosensors as a paradigm-shifting solution for holistic lung cancer diagnosis. We first delineate the biological foundation of key miRNA and protein biomarkers in lung cancer pathogenesis. We then survey the state-of-the-art in biosensing technologies for single-analyte detection, highlighting advances in electrochemical, optical, and plasmonic modalities, along with sophisticated amplification strategies like CRISPR/Cas and catalytic hairpin assembly. The core of the review critically examines the conceptual innovations and progress in dual-biosensing platforms, including designs based on logic gates, dual-mode ratiometric sensing, and integration with microfluidics and smartphone readouts. We explore their profound clinical potential for early detection, molecular subtyping, and real-time therapy monitoring, while also addressing the analytical, standardization, and ethical challenges that must be overcome for clinical translation. We conclude that the integration of miRNA and protein detection into a single biosensor platform represents a monumental leap toward personalized, multiplexed, and point-of-care diagnostics, poised to fundamentally advance the frontiers of precision oncology.