merge_fc_deseq2(featurecounts_file, deseq2_file, output, key_in_fc='Geneid', key_in_deseq2='Unnamed: 0')
:param str featurecounts_file: featurecount like file
:param str deseq2_file: deseq2 result file, separated by comma
:param str output: output
:param str key_in_fc: key column used to merge in featurecount
:param str key_in_deseq2: key column used to merge in deseq2
:return: