1 Zymfentra (Infliximab-dyyb) REal World Cohort STudy

1. Create a prospective cohort of well-phenotyped adult CD, UC and IBDU patients with serial clinical and patient-reported data collected throughout 12 months of Zymfentra (IFX -dyyb) therapy. 2. To determine clinical response and remission rates, course of stool calprotectin values and persistence of therapy with Zymfentra (IFX -dyyb) for induction and maintenance therapy. 3. Assess the correlation of various outcome measures in CD, UC or IBDU (short Crohn's disease activity index (sCDAI), Simple Clinical Colitis Activity Index (SCCAI), Urgency score, Fatigue,SIBDQ, PROMIS measures for depression, anxiety, and social satisfaction and work productivity and activity impairment. 4. Assess the effect of Zymfentra (IFX-dyyb) on patient reported fistula symptoms in patients with CD with pre-existing perianal fistulizing disease. 5. Assess persistence and need for dose escalation therapy of Zymfentra (IFX-dyyb). 6. Assessment of trough levels taken in the setting of standard of care before and after start of Zymfentra (IFX-dyyb).