Background: The role of CN in mRCC was challenged by the results of the CARMENA trial in the targeted therapy (TT) era. We sought to evaluate the role of both upfront and deferred CN in pts receiving modern IO-based and TT regimens. Methods: Pts with synchronous mRCC who received systemic therapy (tx) for mRCC after 2011 were included from the de-identified nationwide Flatiron Health database. We evaluated 3 groups: systemic tx alone, systemic-> CN, and CN-> systemic tx. Overall survival (OS) was calculated from the time of initiation of first therapy – systemic or CN. Patient characteristics were compared using chi-squared tests or t-test. Weighted Kaplan-Meier curves, log-rank tests, and Cox proportional hazards regressions with time-varying covariates were used to assess the effect of tx on survival. Adjustment was conducted via inverse probability of treatment weighing based on the generalized propensity score, estimated via Bayesian Additive Regression Trees. Covariates in the model were age, gender, race, insurance at mRCC diagnosis, and IMDC risk group. Results: Of 1719 pts with mRCC, 972 (56.5%) received systemic tx alone, 605 (35.1%) received CN-> systemic tx, and 142 (8.2%) received systemic->CN. 310 pts received IO or IO/IO, 123 pts received IO+TT and 1152 pts received only TT. The median follow-up was 37.1 months. In adjusted analyses using propensity score weighting and time-varying covariates, CN-> systemic was significantly associated with improved OS compared with systemic tx alone (Table). When stratifying groups by type of systemic treatment (IO and TT), there was improvement of OS in the CN groups compared to systemic tx alone, although we lacked power to reach statistical significance. Among CN-treated patients, the order of systemic tx relative to CN did not change OS (hazard ratio [HR] = 1.00, 95% CI 0.76-1.32, p=0.96). Conclusions: Using a national, EHR-based cohort, which includes a large number of IO treated pts, our findings support an oncologic role for CN in select mRCC pts. The timing of CN, for pts who were able to receive both systemic therapy and CN, may not affect overall outcome. The associated improvement in survival of CN is seen in pts receiving IO and TKI based systemic tx.