The tech sector's high profile march into life sciences, from Alphabet Inc.'s Verily to IBM Corp.'s Watson, hasn't always been smooth. Successes, such as Exscientia Ltd. and Benevolentai Ltd., have almost universally emerged from within the biopharma sector rather than without. Now Palantir Technologies Inc., a data analysis specialist known best for its counterterrorism and defense work, is looking to bridge the gap with an artificial intelligence platform it is billing as an "operating system" for health care and other companies.