Phase 1/2 study evaluates the safety, feasibility, and preliminary antitumor activity of allogeneic dual-target CD70/CAIX CAR-NK cells after fludarabine/cyclophosphamide lymphodepletion in adults with advanced or metastatic clear cell RCC that has progressed after standard therapy. The study is designed to determine a recommended dose and schedule, characterize hepatobiliary safety, and explore whether CD70-high, CAIX-high, or dual-high tumors derive the greatest benefit. Biomarker-defined activity signals will be used to guide whether later development should prioritize CD70, CAIX/CA9, or continued dual-targeting.