Additional Study Information: The purpose of this study is safety, tolerability and efficacy of a combined treatment of LBL-007 and tislelizumab in combination with bevacizumab and capecitabine. LBL-007 and tislelizumab has not yet been approved by the Food and Drug Administration (FDA). Bevacizumab and capecitabine are approved for use in colorectal cancer, but their use in combination with LBL-007 alone or LBL-007 in combination with tislelizumab is not. Tislelizumab affects cells in your immune system, making them more likely to attack cancer cells. Tislelizumab does this by binding to a part of your immune cells called PD-1 (also called programmed cell death-1). PD-1 normally works as a brake. When activated, it makes the immune cell less likely to attack nearby cells. This is important for normal immune system function. It helps prevent your immune cells from attacking healthy cells. However, cancer cells can take advantage of PD-1 to fool the immune system. If a cancer cell activates PD-1 on nearby immune cells, the cancer is mistakenly seen as healthy. Immune cells then leave the cancer cells alone rather than attack them. Tislelizumab is thought to prevent this trick and make immune cells more likely to attack your cancer. Your body's immune cells have another substance present on their surface, which is called LAG-3 (also called lymphocyte activation gene 3). LAG-3 works as another brake. It not only slows down the sharp increase of immune cells with antitumor activity, but also directly affects their immune function. LAG-3 works together with PD-1 to stop your body's immune cells from killing tumor cells. LAG-3 also strengthens the blocking activity of cells which have a curbing function in your immune system further suppressing the immune response. The LBL-007 antibody works by blocking the interaction between LAG-3 and its partners to further release the brake on your immune cells, which may increase the tumor-killing ability of your immune cells.