In primary bladder carcinoma CD8+ cells occupied 26.7 ± 1.4% of tumor area of high-grade luminal NMIBC and 16.8 ± 0.8% (p = 0.001) of tumor tissue with low malignant potential; basal molecular subtype of primary bladder cancers presented a low level of CD8+ expression, which was significantly higher in low-grade tumors (8.0 ± 0.8%) than in highly malignant tissues (5.3 ± 0.7%; p = 0.005). This evidence concerns the gene CD8A and urinary bladder cancer.