CTLA4 and colorectal carcinoma: Immunotherapy also promotes tumour tolerance as regulatory T cells express the CTLA‐4 immune checkpoint receptor, in which m6A‐modified circQSOX1 promotes PGAM1 expression, which in turn facilitates immune escape from CRC through activation of glycolysis and an anti‐CTLA‐4 therapeutic response, thereby promoting CRC tumourigenesis.113