GSTM1 and digestive system cancer: The final combination of 16 significant variables that we identified included one demographic feature (age), one ICPi (nivolumab), six concomitant medications (NSAIDS, antibiotics, PPI, ACEI/ARB, diuretics, and chemotherapeutic agents), four laboratory test indicators (ALb, Hb, eGFR, and D-dimer), and four malignancy types (hepatobiliary cancer, genitourinary cancer, gastrointestinal tract cancer, and lung cancer).