Immunotherapy-related CRP Kinetics in Early and Metastatic Triple-negative Breast Cancer

This study is tracking a blood protein called CRP (C-reactive protein) in women with triple-negative breast cancer (TNBC) who are receiving immunotherapy, to see if CRP levels can predict who responds well to treatment. **You may be eligible if...** - You are a woman 18 or older - You have confirmed triple-negative breast cancer (ER, PR, and HER2 negative) at any stage - You are receiving or about to receive immunotherapy (checkpoint inhibitor) as part of your treatment **You may NOT be eligible if...** - You have a different breast cancer subtype (not triple-negative) - You are not receiving immunotherapy as part of your treatment - You have a condition that causes chronically elevated CRP unrelated to cancer (e.g., active serious infection) Talk to your doctor to see if this trial is right for you.