This study explores treatments for certain types of breast cancer. **Breast cancer** is a disease where cells in the breast grow out of control. It focuses on two types: metastatic triple-negative (TNBC) and ER-positive, HER2-negative breast cancer. "Metastatic" means the cancer has spread to other parts of the body. "Triple-negative" means the cancer does not have receptors for estrogen, progesterone, or HER2 proteins. "ER-positive" means the cancer grows in response to estrogen. "HER2-negative" means it does not grow due to too much HER2 protein.

The study compares **standard chemotherapy** (a treatment that uses drugs to kill cancer cells) alone versus chemotherapy combined with a new treatment called **tocilizumab biosimilar** (a drug that targets certain proteins to stop cancer growth). Participants must be **18 or older** and fit certain health criteria. It involves **42 people** divided into two groups for each type of cancer.

• Participation requires several visits for treatment and monitoring.
• Participants may receive either a single drug or a combination therapy.
• There are specific rules about past treatments and health conditions to join.