A randomized, open, multicenter phase II study of efficacy and safety comparing XELOX and a PD-1 inhibitor and a bevacizumab biosimilar drug (DAITON)with XELOX and a bevacizumab biosimilar drug (DAITON)in the first-line treatment of RAS mutated pMMR /MSS advanced colorectal cancer patients

Interventions: group A :XELOX combined with PD-1 inhibitor and bevacizumab biosimilar;group B :XELOX in combination with bevacizumab biosimilar Primary outcome(s): l Progression-free survival (PFS) was compared and assessed according to RECIST1.1 and IRRECIST Study Design: Parallel