The pros-cons tag wiki states:

For questions asking for advantages and disadvantages of a certain feature.  DO NOT use as the only tag of a question, and use other tags in addition to this one that more accurately define the question.  DO NOT use this in combination with language-comparison.

While the language-comparison usage guide states:

Use this tag on questions comparing different programming languages' implementation of a feature.  DO NOT use this in combination with pros-cons.

There is ongoing discussion what to do with these tags long term, if they should be kept, burnerated, or their meaning changed. Please answer those threads if you think either of these actions should be done.

However, in the meantime please refrain from adding both tags to a question. Either a question is about the advantages/disadvantages of a feature or comparing many different approaches to a problem. Having both makes no sense.

The pros-cons tag wiki states:

For questions asking for advantages and disadvantages of a certain feature. 

DO NOT use as the only tag of a question, and use other tags in addition to this one that more accurately define the question. 

DO NOT use this in combination with language-comparison.

While the language-comparison usage guide states:

Use this tag on questions comparing different programming languages' implementation of a feature. 

DO NOT use this in combination with pros-cons.

There is ongoing discussion what to do with these tags long term, if they should be kept, burnerated, or their meaning changed. Please answer those threads if you think either of these actions should be done.

However, in the meantime please refrain from adding both tags to a question. Either a question is about the advantages/disadvantages of a feature or comparing many different approaches to a problem. Having both makes no sense.