CTLA4 and pancreatic adenocarcinoma: In another case, circ‐UBAP2 was found to be differentially expressed in pancreatic adenocarcinoma (PAAD) and could modulate the expression of CXCR4 and ZEB1, which are linked with M2 macrophages, exhausted T cells and T‐regulatory cells (Tregs), and are positively correlated with PD‐1 and CTLA‐4.47