Background: However, recent evidences suggest that lymphocyte infiltration in tumors (LIT), which is presented in breast cancer prior to the treatment, may predict response to the therapy and a better prognosis. Not only the intensity of lymphocyte infiltration, but also the phenotype of that infiltrate, determine the clinical outcome.Objectives:To evaluate the intensity and composition of the LIT in an operated TNBC and its association with the expression of PD-1, PD-L1 and PD-L2. Methods: This is an observational, descriptive and a retrospective cohort study. The studied population consisted of patients diagnosed with invasive TNBC. Results: LIT was evaluated in 165 patients. The mean intensity of the inflammatory infiltrate was 20%.We observed that 47 (28%) had inflammatory infiltrate ≤5%, 86 (52%) between 5 and 50% and 32 (19%) > 50%. The average OS in each group was, respectively, 85 months, 104 months and 148 months (p = 0.002). We established an ideal cutoff point of 5% of LIT for OS analysis, so that average overall survival was 85 months for patients with LIT≤5% and 136 months for those with infiltrate > 5% (p = 0.001) . We included 76 cases in the TMA for IHC analysis. We established an optimal cutoff point of 5% in this group, we observed that the majority 56 (78.87%) had an inflammatory infiltrate > 5%. With a tendency to benefit in specific cancer survival, for patients with inflammatory infiltrate > 5%, but with no statistical significance. We found an average of 4 and 12% expression of tumor-free PD-L1 and no stroma, respectively. The cutoff point for the labeling of PD-L1 in the stroma was 5%, with 17 (22.4%) presenting > 5% and 31 (40.8%) ≤5%; and in tumor was 1%, with 11 (14.5%) > 1% and 51 (67%) ≤1%. There was no association between PD-L1 expression and OS. We found a positive and statistically significant correlation of LIT with labeling PD-L1 in stroma (p = 0.001) and in tumor (p = 0.028). Conclusions: In TNBC, TII above 5% is associated with the increasing of OS. TII is associated with a number of cells labeled positively for PD-L1 both in stroma and in tumor. PD-L1 was not associated with OS. Increased number of FOXP3+ and of PTEN marking cells are associated with better OS.