CD28 and non-small cell lung carcinoma: In addition, a study aimed at elucidating the prognostic relevance of exo-PD-L1 and CD28 in NSCLC patients subjected to ICI treatment uncovered that patients with elevated exo-PD-L1 expression coupled with reduced CD28 levels displayed a shorter progression-free survival, underscoring the importance of considering baseline exo-PD-L1 and CD28 levels as potential prognostic indicators for the outcomes of PD-1-based therapeutic interventions (Zhang C. et al., 2020).