Tricare , formerly known as CHAMPUS, provides civilian benefits for military personnel, and their dependents. Tricare for Life (TFL) was designed to offer secondary coverage to Medicare for all who have Medicare Part A and Part B. There are very few ways one can have Tricare without having Part B.
Tricare, formerly known as CHAMPUS, is a health care program of the U.S. Dept of Defense Military Health System. TFL, Tricare for Life, offers secondary coverage to Medicare for all beneficiaries who have both Medicare Parts A and B. There are very few incidences where one can get this coverage without having Part B, and those incidences are temporary.
Here is a helpful link to explain TFL and Medicare.
https://www.tricare4u.com/apps-portal/tricareapps-app/static/pdf/TRICARE_and_Medicare_Turning_65_Fact_Sheet_2011_508.pdf