TNFRSF4 and vitamin D deficiency: In this work, our purpose was to evaluate the evolution of different immune suppressor cells (MDSCs, Tregs, and both exhausted PD-1+OX40- and CTLA-4+OX40- T cells) throughout the R2-GDP treatment in R/R DLBCL patients with normal vitamin D (NVD) levels and vitamin D deficiency (VDD) (>15 ng/mL and <15 ng/mL, respectively), recruited in the R2-GDP-GOTEL study.