Hi, It really depends on what you have taken in your previous years. Considering a general situation that you have taken PCMB. The two best fields you can enter in to get a secured job is Medical and Engineering. Classifying both the branches more on the basis of secured job opportunities are:

Engineering:

1. Environmental.

2. Software.

3. Computer Science.

4. Data Science.

5. Mechanical.

Career options that will require biology as a subject:

1. Anthropologist.

2. Biochemist.

3. Epidemiologist.

4. Forensic scientist.

5. Analytical chemist.

Others:

1. Psychologist.

2. Food technologist.

3. Crime scene investigator.

4. Business analytics.

These are some of the most emerging branches you can try. Also, some of them are very common but also have a lot of scope for growth as they are new. It is best that you look into what you really like doing and ask yourself is it really something you see yourself working on for the rest of your life or is it just a hobby. The downside of choosing a very small topic as your degree is that it is very difficult to go back and change what you want to do. All the best!