This was a retrospective hospital-based study of patients with NSCLC treated with Nivolumab in the University Hospital of Salamanca....When the sample was analysed according to the positivity or negativity of PD-L1 expression, statistically significant differences were identified in the subgroup of patients with negative PD-L1. For this subgroup of patients, OS was 13 months (95% CI 11.0–15.0) in patients with p53 levels of < 5% and was 39 months (95% CI 0.0–78.5) in patients with p53 levels of ≥ 5% (HR = 0.298 [95% CI 0.093–0.950]; p = 0.024) (Fig. 5). The PFS was 3 months (95% CI 1.9–4.1) in patients with p53 levels of <5% and was 7 months (95% CI 1.5–12.5) in patients with p53 levels of ≥ 5% (HR = 0.478 [95% CI 0.186–1.231]; p = 0.070)....A trend toward a greater response to ICIs was observed in the PFS and OS of patients with high expression of p53 by IHC (TP53 mutation), especially in the PD-L1 negative adenocarcinoma subgroup.