CD4 and Sepsis: Considering the research spotlight on finding early, valuable, and cost-effective predictors for sepsis outcomes, this study aimed to investigate sepsis-induced apoptosis and its pathways, assessing the changes in PD-1 and PD-L1 serum values, CD4+ T cells, CD8+ T cells, and Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation (APACHE II) severity scores, on day 1 and day 5, in patients presenting with either sepsis or septic shock.